From 4961a748d4082a19e2ec8e34f90e8d546d582350 Mon Sep 17 00:00:00 2001 From: sjat Date: Wed, 24 Jun 2026 17:39:34 +0200 Subject: [PATCH] docs(rack): shelf-mounted devices implementation plan --- notes/dev/plans/2026-06-24-rack-shelves.md | 677 +++++++++++++++++++++ 1 file changed, 677 insertions(+) create mode 100644 notes/dev/plans/2026-06-24-rack-shelves.md diff --git a/notes/dev/plans/2026-06-24-rack-shelves.md b/notes/dev/plans/2026-06-24-rack-shelves.md new file mode 100644 index 0000000..c751342 --- /dev/null +++ b/notes/dev/plans/2026-06-24-rack-shelves.md @@ -0,0 +1,677 @@ +# Shelf-Mounted Devices Implementation Plan + +> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking. + +**Goal:** Model cabinet/tower PCs that sit on a rack shelf — the shelf reserves a U-range, occupants attach via `mounted_on`/`shelf_face`/`shelf_slot` — and render them as side-by-side boxes in the elevation. + +**Architecture:** Extend `scripts/gen_rack.py`: a `mounted_on` branch in `validate_item`, a skip in `check_overlaps`, a new `check_shelves` cross-item validator, and shelf rendering in `render_svg` (a shelf strip plus per-occupant boxes subdividing the column) and `render_page` (occupancy rows for mounted devices). Then populate the worked example. No generator-config or CI changes. + +**Tech Stack:** Python 3 (stdlib + PyYAML only), pytest, MkDocs Material, Forgejo Actions CI. + +**Spec:** `notes/dev/specs/2026-06-24-rack-shelves-design.md`. + +## Global Constraints + +- Scripts use **stdlib + PyYAML only**; deterministic and offline (copy existing `gen_rack.py` style). No randomness/time in generated output. +- `re` and `yaml` are already imported in `scripts/gen_rack.py`; do not add new imports. +- Validation failures raise `SchemaError`; `generate` prints `ERROR: …` to stderr and returns `1`, **writing nothing** on failure. +- A **mounted device** declares `mounted_on` (str), `shelf_face` ∈ {front, rear}, `shelf_slot` (int ≥ 1), and **omits** `rack_u`/`u_height`/`rack_face`. A **shelf** (`kind: shelf`) is placed normally (`rack_u`/`u_height`/`rack_face: both`) and reserves the assembly's U-range. +- Peer/PDU/grouping fields (`power:`, `links:`, `cluster:`) on a mounted device are unchanged — they key off hostname, not placement. +- Reuse the existing `item()` and `_write_item` test helpers in `tests/test_gen_rack.py`; add a local `shelf()` helper where noted. +- `isinstance(x, int)` style (bool-is-int acceptable, matching existing code). +- Provisional placeholder data only (matches the existing `srvNN` positions and power/network demos). +- **No edits** to `mkdocs.yml`, `Makefile`, `.forgejo/workflows/docs.yml`, or `scripts/overview_config.yml` (`shelf`/`server` already in the enum; drift already covers `racks/`). +- `mkdocs build --strict` must pass; `make docs-check` must exit 0 after regeneration. + +--- + +### Task 1: Validation — mounted branch, overlap skip, `check_shelves` (TDD) + +**Files:** +- Modify: `scripts/gen_rack.py` (add `SHELF_FACES`; `validate_item` mounted branch; `check_overlaps` skip; new `check_shelves`; call it in `generate`) +- Modify: `tests/test_gen_rack.py` (append tests + a `shelf()` helper) + +**Interfaces:** +- Consumes: `SchemaError`, `item()`/`_write_item` helpers, `generate`. +- Produces: + - `SHELF_FACES = {"front", "rear"}` (constant) + - `check_shelves(items: list[dict]) -> None` — raises `SchemaError` on a bad mount. + - `validate_item` and `check_overlaps` gain mounted-item handling. + +- [ ] **Step 1: Append a `shelf()` helper and failing tests to `tests/test_gen_rack.py`** + +Add near the top, just after the existing `item()` helper: + +```python +def shelf(**kw): + base = {"hostname": "shf01", "kind": "shelf", "status": "in-use", + "rack": "rack01", "rack_u": 37, "u_height": 10, "rack_face": "both"} + base.update(kw) + return base +``` + +Append these tests at the end of the file: + +```python +def test_validate_accepts_mounted_item(): + gen_rack.validate_item(item(hostname="srv01", mounted_on="shf01", + shelf_face="front", shelf_slot=1)) + + +def test_validate_rejects_mounted_with_rack_u(): + with pytest.raises(gen_rack.SchemaError): + gen_rack.validate_item(item(hostname="srv01", mounted_on="shf01", + shelf_face="front", shelf_slot=1, rack_u=5)) + + +def test_validate_rejects_mounted_bad_shelf_face(): + with pytest.raises(gen_rack.SchemaError): + gen_rack.validate_item(item(hostname="srv01", mounted_on="shf01", + shelf_face="left", shelf_slot=1)) + + +def test_validate_rejects_mounted_bad_slot(): + with pytest.raises(gen_rack.SchemaError): + gen_rack.validate_item(item(hostname="srv01", mounted_on="shf01", + shelf_face="front", shelf_slot=0)) + + +def test_overlaps_skips_mounted_items(): + items = [ + item(hostname="a", mounted_on="shf01", shelf_face="front", shelf_slot=1), + item(hostname="b", mounted_on="shf01", shelf_face="front", shelf_slot=2), + ] + gen_rack.check_overlaps(items) # no raise — mounted items claim no U-range + + +def test_check_shelves_accepts_valid_mount(): + items = [shelf(), + item(hostname="srv01", mounted_on="shf01", + shelf_face="front", shelf_slot=1)] + gen_rack.check_shelves(items) + + +def test_check_shelves_rejects_missing_shelf(): + items = [item(hostname="srv01", mounted_on="ghost", + shelf_face="front", shelf_slot=1)] + with pytest.raises(gen_rack.SchemaError): + gen_rack.check_shelves(items) + + +def test_check_shelves_rejects_non_shelf_target(): + items = [ + item(hostname="sw01", kind="switch", rack_u=10, u_height=1, + rack_face="front"), + item(hostname="srv01", mounted_on="sw01", + shelf_face="front", shelf_slot=1), + ] + with pytest.raises(gen_rack.SchemaError): + gen_rack.check_shelves(items) + + +def test_check_shelves_rejects_duplicate_slot(): + items = [shelf(), + item(hostname="srv01", mounted_on="shf01", + shelf_face="front", shelf_slot=1), + item(hostname="srv02", mounted_on="shf01", + shelf_face="front", shelf_slot=1)] + with pytest.raises(gen_rack.SchemaError): + gen_rack.check_shelves(items) + + +def test_generate_returns_1_on_dangling_mount(tmp_path): + hw = tmp_path / "hardware" + out = tmp_path / "out" + hw.mkdir() + _write_item( + hw, "srv01", + "---\nhostname: srv01\nkind: server\nstatus: in-use\n" + "rack: rack01\nmounted_on: ghost\nshelf_face: front\nshelf_slot: 1\n---\n", + ) + rc = gen_rack.generate(hw, out) + assert rc == 1 + assert not (out / "rack01.md").exists() +``` + +- [ ] **Step 2: Run to verify failure** + +Run: `pytest tests/test_gen_rack.py -q` +Expected: FAIL — `AttributeError: module 'gen_rack' has no attribute 'check_shelves'` (and the mounted-validation tests fail because `validate_item` rejects the missing `rack_face`). + +- [ ] **Step 3: Add the `SHELF_FACES` constant** + +In `scripts/gen_rack.py`, just after the existing `ZERO_U_FACES = {"left", "right"}` line, add: + +```python +SHELF_FACES = {"front", "rear"} +``` + +- [ ] **Step 4: Add the mounted branch to `validate_item`** + +In `validate_item`, the function currently begins: + +```python +def validate_item(fm: dict) -> None: + name = fm.get("hostname") or fm.get("_path", "?") + rack = fm.get("rack") + if not isinstance(rack, str) or not rack: + raise SchemaError(f"{name}: rack must be a non-empty string") + face = fm.get("rack_face") +``` + +Insert the mounted branch between the `rack` check and the `face = …` line, so it reads: + +```python +def validate_item(fm: dict) -> None: + name = fm.get("hostname") or fm.get("_path", "?") + rack = fm.get("rack") + if not isinstance(rack, str) or not rack: + raise SchemaError(f"{name}: rack must be a non-empty string") + if "mounted_on" in fm: + mounted_on = fm.get("mounted_on") + if not isinstance(mounted_on, str) or not mounted_on: + raise SchemaError(f"{name}: mounted_on must be a non-empty string") + for forbidden in ("rack_u", "u_height", "rack_face"): + if forbidden in fm: + raise SchemaError( + f"{name}: mounted item must omit {forbidden}" + ) + sface = fm.get("shelf_face") + if sface not in SHELF_FACES: + raise SchemaError( + f"{name}: shelf_face={sface!r} not in {sorted(SHELF_FACES)}" + ) + slot = fm.get("shelf_slot") + if not isinstance(slot, int) or slot < 1: + raise SchemaError(f"{name}: shelf_slot must be an integer >= 1") + return + face = fm.get("rack_face") +``` + +(The rest of `validate_item` — the `face`/0U/U-range checks — is unchanged.) + +- [ ] **Step 5: Skip mounted items in `check_overlaps`** + +In `check_overlaps`, the loop body currently starts: + +```python + for fm in items: + face = fm.get("rack_face") + if face in ZERO_U_FACES: + continue +``` + +Add a mounted skip as the first thing in the loop: + +```python + for fm in items: + if "mounted_on" in fm: + continue + face = fm.get("rack_face") + if face in ZERO_U_FACES: + continue +``` + +- [ ] **Step 6: Add `check_shelves` after `check_overlaps`** + +Add this function immediately after `check_overlaps` in `scripts/gen_rack.py`: + +```python +def check_shelves(items: list[dict]) -> None: + """Validate shelf-mounted devices within one rack. + + Every mounted_on resolves to a placed kind:shelf item in the same rack; + no two devices share (shelf, face, slot). + """ + by_host = {fm.get("hostname"): fm for fm in items} + occupied: dict[tuple[str, str, int], str] = {} + for fm in items: + if "mounted_on" not in fm: + continue + name = fm.get("hostname", "?") + shelf_name = fm["mounted_on"] + target = by_host.get(shelf_name) + if target is None: + raise SchemaError( + f"{name}: mounted_on={shelf_name!r} is not in this rack" + ) + if target.get("kind") != "shelf": + raise SchemaError( + f"{name}: mounted_on={shelf_name!r} is not a kind:shelf item" + ) + if not isinstance(target.get("rack_u"), int) or not isinstance( + target.get("u_height"), int + ): + raise SchemaError( + f"{name}: shelf {shelf_name!r} is not placed (needs rack_u/u_height)" + ) + key = (shelf_name, fm["shelf_face"], fm["shelf_slot"]) + if key in occupied: + raise SchemaError( + f"{shelf_name} {fm['shelf_face']} slot {fm['shelf_slot']}: " + f"{name} overlaps {occupied[key]}" + ) + occupied[key] = name +``` + +- [ ] **Step 7: Wire `check_shelves` into `generate`** + +In `generate`, the per-rack validation loop currently reads: + +```python + try: + check_overlaps(ritems) + validate_power(ritems) + validate_links(ritems, hw_index) + except SchemaError as e: + errors.append(f"{rack}: {e}") +``` + +Add `check_shelves(ritems)`: + +```python + try: + check_overlaps(ritems) + validate_power(ritems) + validate_links(ritems, hw_index) + check_shelves(ritems) + except SchemaError as e: + errors.append(f"{rack}: {e}") +``` + +- [ ] **Step 8: Run to verify pass** + +Run: `pytest tests/test_gen_rack.py -q` +Expected: PASS (all prior tests + 10 new). + +- [ ] **Step 9: Commit** + +```bash +git add scripts/gen_rack.py tests/test_gen_rack.py +git commit -m "feat(rack): validate shelf-mounted devices (mounted_on/shelf_face/shelf_slot)" +``` + +--- + +### Task 2: Rendering — shelf strip + occupant boxes + occupancy rows (TDD) + +**Files:** +- Modify: `scripts/gen_rack.py` (`render_svg` shelf drawing; `render_page` occupancy) +- Modify: `tests/test_gen_rack.py` (append tests) + +**Interfaces:** +- Consumes: `render_svg`, `render_page`, the `shelf()` helper (Task 1). +- Produces: `render_svg`/`render_page` render shelves and mounted occupants. No new public function. + +- [ ] **Step 1: Append failing tests to `tests/test_gen_rack.py`** + +```python +def test_render_svg_draws_shelf_and_occupants(): + items = [ + shelf(), + item(hostname="srv01", mounted_on="shf01", shelf_face="front", shelf_slot=1), + item(hostname="srv02", mounted_on="shf01", shelf_face="front", shelf_slot=2), + item(hostname="srv03", mounted_on="shf01", shelf_face="rear", shelf_slot=1), + ] + svg = gen_rack.render_svg("rack01", items) + assert "shf01" in svg + assert "srv01" in svg and "srv02" in svg and "srv03" in svg + # the shelf is NOT drawn as a generic full-height device box + assert "shf01 (U37" not in svg + + +def test_render_svg_shelf_is_deterministic(): + base = [ + shelf(), + item(hostname="srv02", mounted_on="shf01", shelf_face="front", shelf_slot=2), + item(hostname="srv01", mounted_on="shf01", shelf_face="front", shelf_slot=1), + ] + assert gen_rack.render_svg("rack01", base) == gen_rack.render_svg( + "rack01", list(reversed(base)) + ) + + +def test_render_page_lists_mounted_devices(): + items = [shelf(), + item(hostname="srv01", mounted_on="shf01", + shelf_face="front", shelf_slot=1)] + page = gen_rack.render_page("rack01", items) + assert "../../hardware/srv01.md" in page + assert "front · shf01/1" in page + assert "U37–U46" in page # mounted device shows its shelf's U-range +``` + +- [ ] **Step 2: Run to verify failure** + +Run: `pytest tests/test_gen_rack.py -q` +Expected: FAIL — `test_render_page_lists_mounted_devices` raises `KeyError: 'rack_u'` (occupancy loop has no mounted handling) and the SVG tests fail (`shf01`/occupant boxes not drawn; the shelf is drawn as a generic box so `"shf01 (U37"` is present). + +- [ ] **Step 3: Render shelves in `render_svg`** + +In `render_svg`, the generic device loop currently reads: + +```python + for fm in items: + face = fm.get("rack_face") + if face in ("front", "both"): + draw_device(fm, front_x) + if face in ("rear", "both"): + draw_device(fm, rear_x) +``` + +Replace it with a version that skips shelves and mounted items: + +```python + for fm in items: + if fm.get("kind") == "shelf" or "mounted_on" in fm: + continue + face = fm.get("rack_face") + if face in ("front", "both"): + draw_device(fm, front_x) + if face in ("rear", "both"): + draw_device(fm, rear_x) +``` + +Then, immediately before the final `p.append("")` line, add the shelf drawing: + +```python + SHELF_STRIP_H = 6 + shelves = [i for i in items if i.get("kind") == "shelf"] + mounted = [i for i in items if "mounted_on" in i] + + def draw_shelf(fm: dict) -> None: + u = fm["rack_u"] + h = fm["u_height"] + y = u_y(u) + block_h = h * U_H + strip_y = y + block_h - SHELF_STRIP_H + avail_h = block_h - SHELF_STRIP_H + shelf_color = KIND_COLORS.get("shelf", DEFAULT_COLOR) + sname = fm.get("hostname", "?") + for col_x, sface in ((front_x, "front"), (rear_x, "rear")): + occ = sorted( + (m for m in mounted + if m.get("mounted_on") == sname + and m.get("shelf_face") == sface), + key=lambda m: (m.get("shelf_slot", 0), m.get("hostname", "")), + ) + n = len(occ) + for idx, m in enumerate(occ): + sub_w = COL_W // n + bx = col_x + idx * sub_w + bw = (COL_W - idx * sub_w) if idx == n - 1 else sub_w + mcolor = KIND_COLORS.get(m.get("kind", ""), DEFAULT_COLOR) + mname = m.get("hostname", "?") + p.append( + f'' + ) + p.append( + f'{_esc(mname)}' + ) + p.append( + f'' + ) + p.append( + f'{_esc(sname)}' + ) + + for fm in sorted(shelves, key=lambda s: s.get("hostname", "")): + draw_shelf(fm) +``` + +- [ ] **Step 4: Render mounted devices in the `render_page` occupancy table** + +In `render_page`, the occupancy loop currently reads: + +```python + for fm in items: + name = fm.get("hostname", "?") + link = f"[{name}](../../hardware/{name}.md)" + face = fm.get("rack_face", "") + if face in ZERO_U_FACES: + urange = "0U" + else: + u = fm["rack_u"] + h = fm["u_height"] + urange = f"U{u}" if h == 1 else f"U{u}–U{u + h - 1}" + lines.append( + f"| {urange} | {link} | {fm.get('kind', '')} | {face} " + f"| {fm.get('status', '')} |" + ) +``` + +Replace that whole loop with one that orders mounted devices right after their +shelf and renders their shelf-relative position: + +```python + by_host = {fm.get("hostname"): fm for fm in items} + mounted_by_shelf: dict[str, list[dict]] = {} + for fm in items: + if "mounted_on" in fm: + mounted_by_shelf.setdefault(fm["mounted_on"], []).append(fm) + + def occ_row(fm: dict) -> str: + name = fm.get("hostname", "?") + link = f"[{name}](../../hardware/{name}.md)" + if "mounted_on" in fm: + target = by_host.get(fm["mounted_on"]) + if target and isinstance(target.get("rack_u"), int): + su = target["rack_u"] + sh = target["u_height"] + urange = f"U{su}" if sh == 1 else f"U{su}–U{su + sh - 1}" + else: + urange = "—" + face = ( + f"{fm.get('shelf_face', '')} · " + f"{fm['mounted_on']}/{fm.get('shelf_slot', '')}" + ) + else: + face = fm.get("rack_face", "") + if face in ZERO_U_FACES: + urange = "0U" + else: + u = fm["rack_u"] + h = fm["u_height"] + urange = f"U{u}" if h == 1 else f"U{u}–U{u + h - 1}" + return ( + f"| {urange} | {link} | {fm.get('kind', '')} | {face} " + f"| {fm.get('status', '')} |" + ) + + for fm in _sorted_items([i for i in items if "mounted_on" not in i]): + lines.append(occ_row(fm)) + if fm.get("kind") == "shelf": + occ = sorted( + mounted_by_shelf.get(fm.get("hostname"), []), + key=lambda m: (m.get("shelf_face", ""), m.get("shelf_slot", 0)), + ) + for m in occ: + lines.append(occ_row(m)) +``` + +(The `items = _sorted_items(items)` line at the top of `render_page` and the +graph sections above are unchanged.) + +- [ ] **Step 5: Run to verify pass** + +Run: `pytest tests/test_gen_rack.py -q` +Expected: PASS (all prior tests + 3 new). + +- [ ] **Step 6: Commit** + +```bash +git add scripts/gen_rack.py tests/test_gen_rack.py +git commit -m "feat(rack): render shelf strip, occupant boxes, and mounted occupancy rows" +``` + +--- + +### Task 3: Populate the shelf demo, regenerate + +**Files:** +- Create: `docs/hardware/shf01.md` +- Modify: `docs/hardware/srv01.md`, `srv02.md`, `srv03.md` (convert to mounted) +- Regenerate: `docs/hardware/index.md`, `docs/infrastructure/racks/rack01.md`, `docs/infrastructure/racks/rack01-elevation.svg` + +**Interfaces:** +- Consumes: `make docs-index`, `make test`, `mkdocs build --strict`, `make docs-check`. + +> **Operator note — provisional data.** The shelf placement and the front/rear/slot assignments are placeholders matching the worked example (TaPPaaS: srv01/srv02 front, srv03 rear, on a shelf reserving U37–U46). `check_shelves`/`check_overlaps` reject inconsistent data loudly. + +- [ ] **Step 1: Create the shelf file** + +Create `docs/hardware/shf01.md`: + +```markdown +--- +hostname: shf01 +kind: shelf +status: in-use +rack: rack01 +rack_u: 37 +u_height: 10 +rack_face: both +cluster: tappaas +--- + +## Notes + +- Provisional placeholder shelf holding the TaPPaaS nodes (srv01/srv02 front, srv03 rear). +``` + +- [ ] **Step 2: Convert `srv01.md` to mounted** + +In `docs/hardware/srv01.md`, replace these three frontmatter lines: + +```yaml +rack_u: 1 +u_height: 1 +rack_face: front +``` + +with: + +```yaml +mounted_on: shf01 +shelf_face: front +shelf_slot: 1 +``` + +Leave everything else (including `cluster: tappaas`, `power:`, `links:`) unchanged. + +- [ ] **Step 3: Convert `srv02.md` to mounted and tag its cluster** + +In `docs/hardware/srv02.md`, replace these three frontmatter lines: + +```yaml +rack_u: 2 +u_height: 1 +rack_face: front +``` + +with: + +```yaml +mounted_on: shf01 +shelf_face: front +shelf_slot: 2 +``` + +Then add a `cluster: tappaas` line immediately after the `status: staging` line, so the top reads: + +```yaml +hostname: srv02 +kind: server +status: staging +cluster: tappaas +location: The pile +``` + +- [ ] **Step 4: Convert `srv03.md` to mounted and tag its cluster** + +In `docs/hardware/srv03.md`, replace these three frontmatter lines: + +```yaml +rack_u: 3 +u_height: 1 +rack_face: front +``` + +with: + +```yaml +mounted_on: shf01 +shelf_face: rear +shelf_slot: 1 +``` + +Then add a `cluster: tappaas` line immediately after the `status: staging` line: + +```yaml +hostname: srv03 +kind: server +status: staging +cluster: tappaas +location: The pile +``` + +- [ ] **Step 5: Regenerate all indices and rack artifacts** + +Run: `make docs-index` +Expected: `gen_overview.py` rewrites `docs/hardware/index.md` (now listing `shf01` under Shelves); `gen_rack.py` prints `Wrote rack01.md + rack01-elevation.svg (10 item(s))`, exit 0 (no schema error). + +- [ ] **Step 6: Confirm the shelf and mounted devices rendered** + +Run: `grep -c "shf01/" docs/infrastructure/racks/rack01.md` +Expected: `3` (occupancy notes `front · shf01/1`, `front · shf01/2`, `rear · shf01/1`). + +Run: `grep -q "shf01" docs/infrastructure/racks/rack01-elevation.svg && echo OK` +Expected: `OK` (shelf strip drawn). + +Run: `grep -q "U37–U46" docs/infrastructure/racks/rack01.md && echo OK` +Expected: `OK` (mounted devices show the shelf's U-range). + +- [ ] **Step 7: Run the full test suite** + +Run: `make test` +Expected: PASS. + +- [ ] **Step 8: Build the site strictly** + +Run: `mkdocs build --strict` (or `python3 -m mkdocs build --strict` if `mkdocs` is not on PATH) +Expected: build succeeds with no warnings-as-errors. + +- [ ] **Step 9: Confirm the drift guard is satisfied** + +Run: `make docs-check` +Expected: exit 0. + +- [ ] **Step 10: Commit** + +```bash +git add docs/hardware/ docs/infrastructure/racks/ +git commit -m "feat(rack): place TaPPaaS nodes on shelf shf01 (provisional)" +``` + +--- + +## Self-Review + +**Spec coverage (`2026-06-24-rack-shelves-design.md`):** +- Container model: shelf placed + reserves U-range; mounted devices via `mounted_on`/`shelf_face`/`shelf_slot` — Task 1 (validation), Task 3 (data). ✔ +- `validate_item` mounted branch (forbid rack_u/u_height/rack_face; require shelf_face/shelf_slot) — Task 1 Step 4. ✔ +- `check_overlaps` skips mounted items — Task 1 Step 5. ✔ +- `check_shelves` (resolves to placed kind:shelf in rack; unique slot) wired into `generate` — Task 1 Steps 6–7. ✔ +- SVG shelf strip + subdivided occupant boxes — Task 2 Step 3. ✔ +- Occupancy rows for mounted devices (shelf U-range + `face · shelf/slot`, ordered after the shelf) — Task 2 Step 4. ✔ +- Power/network unchanged — no edits to `render_power`/`render_network`; mounted devices keep `power:`/`links:`. ✔ +- Demo data (shf01 U37–U46; srv01/srv02 front 1–2, srv03 rear 1; cluster tappaas) — Task 3. ✔ +- No mkdocs/Makefile/CI/overview_config changes — Global Constraints. ✔ + +**Placeholder scan:** No "TBD"/"handle edge cases"/"similar to Task N". The provisional demo placements are real-data-dependent and explicitly bounded. + +**Type consistency:** `SHELF_FACES: set`; `check_shelves(items) -> None` (raises `SchemaError`), called per-rack alongside `check_overlaps`/`validate_power`/`validate_links`; `render_svg`/`render_page` -> `str`. Mounted items are identified uniformly by `"mounted_on" in fm` across `validate_item`, `check_overlaps`, `check_shelves`, `render_svg`, and `render_page`. The `shelf()` test helper (Task 1) is reused in Task 2. Field names (`mounted_on`, `shelf_face`, `shelf_slot`) match across tasks, tests, and demo data.