fix(mcp,editor): close URL-validation bypasses surfaced by Phase 8 P4

Phase 8 parallel validation flagged two boundaries where malicious URLs
(javascript:, file:, external http:, data:text/html, ...) could be
persisted despite the AssetUrl allowlist added in Phase 7 A7:

1. `save_scene({ includeCurrentScene: false, graph })` — the graph arg
   was treated as opaque (`z.record(z.string(), z.unknown())`) and
   written to the store without re-running AnyNode.safeParse.

2. `POST /api/scenes { graph }` in the editor API — same issue; the
   Zod `graphSchema` accepted anything object-shaped.

Fixes:
- `save-scene.ts`: when `includeCurrentScene === false`, iterate every
  node and run `AnyNode.safeParse`; collect issues and throw
  `McpError(InvalidParams, 'graph_invalid', { errors })` on any
  failure.
- `app/api/scenes/route.ts`: replace `graphSchema` with a structured
  `z.object({ nodes, rootNodeIds, collections? })` + `superRefine`
  that runs `AnyNode.safeParse` on every node. Invalid → 400 with
  detailed issue paths.

Tests:
- Added `save_scene` regression test for the P4 attack
  (item.asset.src = 'javascript:alert(1)') — expected error.
- Fixed the existing `includeCurrentScene=false` test to use a
  schema-compliant site node id (the prior `id: 'root'` now fails
  the AnyNode parse, which is the desired strict behaviour).
- Full suite: 294 pass / 0 fail.

Also adds Phase 8 test-reports/phase8/** (10 agents, ~15 scripts +
markdown reports) documenting the validation run, plus minor biome
cleanups to the Phase 5/7 test artefacts (removed stale
`// biome-ignore` suppression comments that now resolve to the
already-off `noConsole` rule).

Phase 8 result summary (10 parallel agents, stdio MCP transport with
isolated data dirs):
- P1 templates: 18/18 PASS
- P2 variants: 6/7 mutations + determinism + save + combined + error
- P3 locking: 12/12 PASS (MCP + editor HTTP If-Match)
- P4 URL hardening: fixed 2 bypasses (see above)
- P5 photo-to-scene: 6/6 PASS
- P6 Casa del Sol via save_scene: 13/13 PASS
- P7 editor HTTP API: 18/18 PASS
- P8 concurrency: 4/5 PASS, flagged 2 real filesystem-store races
  (expectedVersion CAS gap + .index.json drift under parallel writes)
- P9 edge cases: 13/13 PASS (size cap, slug safety, bad inputs)
- P10 full sweep: 37/37 PASS (30 tools + 4 resources + 3 prompts)

Known follow-ups:
- FilesystemSceneStore needs a proper lockfile / atomic CAS to fix
  the P8 concurrency bugs (low priority: single-writer MCP is the
  typical case).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/mcp/test-reports/phase8/p10-full-sweep.md

@@ -0,0 +1,122 @@
+# Phase 8 P10 — full sweep (stdio MCP)
+
+Generated: 2026-04-19T18:21:20.973Z
+
+## Summary
+
+- Transport: stdio (`bun packages/mcp/dist/bin/pascal-mcp.js --stdio`)
+- Data dir: `/tmp/pascal-phase8-p10`
+- Sampling: mocked via `client.setRequestHandler(CreateMessageRequestSchema, …)`
+- Tools listed: **30**
+- Resources listed: **3** static + **1** template
+- Prompts listed: **3**
+- Total entries exercised: **37**
+- PASS: **37** / PARTIAL: **0** / FAIL: **0**
+- Run time: **152 ms**
+
+## Listed tools
+
+```
+analyze_floorplan_image
+analyze_room_photo
+apply_patch
+check_collisions
+create_from_template
+create_level
+create_wall
+cut_opening
+delete_node
+delete_scene
+describe_node
+duplicate_level
+export_glb
+export_json
+find_nodes
+generate_variants
+get_node
+get_scene
+list_scenes
+list_templates
+load_scene
+measure
+photo_to_scene
+place_item
+redo
+rename_scene
+save_scene
+set_zone
+undo
+validate_scene
+```
+
+## Listed resources
+
+```
+(static)
+pascal://catalog/items
+pascal://scene/current
+pascal://scene/current/summary
+
+(templates)
+pascal://constraints/{levelId}
+```
+
+## Listed prompts
+
+```
+from_brief
+iterate_on_feedback
+renovation_from_photos
+```
+
+## Pass matrix — tools
+
+| # | Tool | Status | Note |
+|---|------|--------|------|
+| 1 | `list_templates` | PASS | 3 templates |
+| 2 | `create_from_template` | PASS | templateId=two-bedroom nodes=25 |
+| 3 | `get_scene` | PASS | 25 nodes / 1 roots |
+| 4 | `get_node` | PASS | type=site |
+| 5 | `describe_node` | PASS | type=site children=1 |
+| 6 | `find_nodes` | PASS | 1 level(s) |
+| 7 | `measure` | PASS | d=6.403m |
+| 8 | `apply_patch` | PASS | applied=1 |
+| 9 | `create_level` | PASS | levelId=level_7fjtu570j6yyxcm4 |
+| 10 | `create_wall` | PASS | wallId=wall_2b2og8j9nrr6jk6t |
+| 11 | `place_item` | PASS | itemId=item_efdmfnownqwa3yd4 |
+| 12 | `cut_opening` | PASS | openingId=door_c0cul6bctrwf76md |
+| 13 | `set_zone` | PASS | zoneId=zone_7ljy8xitu0km2q8d |
+| 14 | `duplicate_level` | PASS | newLevelId=level_i5yq9hk2kwd9unpw nodes=28 |
+| 15 | `delete_node` | PASS | deleted 28 nodes |
+| 16 | `undo` | PASS | undone=1 |
+| 17 | `redo` | PASS | redone=1 |
+| 18 | `export_json` | PASS | 21051 chars |
+| 19 | `export_glb` | PASS | bytes/b64=0 |
+| 20 | `validate_scene` | PASS | valid=true errors=0 |
+| 21 | `check_collisions` | PASS | 0 collision(s) |
+| 22 | `analyze_floorplan_image` | PASS | walls=4 rooms=1 conf=0.82 |
+| 23 | `analyze_room_photo` | PASS | w=4m fixtures=2 |
+| 24 | `save_scene` | PASS | id=7b7ca35340e3 v=1 nodes=31 |
+| 25 | `list_scenes` | PASS | 1 scene(s) |
+| 26 | `load_scene` | PASS | id=7b7ca35340e3 nodes=31 |
+| 27 | `generate_variants` | PASS | 2 variants, ids=2 |
+| 28 | `photo_to_scene` | PASS | sceneId=fbde55412851 walls=4 rooms=1 |
+| 29 | `rename_scene` | PASS | name=p10 base renamed |
+| 30 | `delete_scene` | PASS | deleted=86366d07b242 |
+
+## Pass matrix — resources
+
+| # | Resource | Status | Note |
+|---|----------|--------|------|
+| 1 | `pascal://scene/current` | PASS | 8 nodes / 1 roots |
+| 2 | `pascal://scene/current/summary` | PASS | 425 chars of markdown |
+| 3 | `pascal://catalog/items` | PASS | 0 items |
+| 4 | `pascal://constraints/{levelId}` | PASS | slabs=0 wallPolys=4 |
+
+## Pass matrix — prompts
+
+| # | Prompt | Status | Note |
+|---|--------|--------|------|
+| 1 | `from_brief` | PASS | 1 message(s) |
+| 2 | `iterate_on_feedback` | PASS | 1 message(s) |
+| 3 | `renovation_from_photos` | PASS | 6 message(s) |