feat(task-5): planar faces, measured room labels and the foreign-plan reader

engineering/arch/faces.py finds the closed faces a set of straight segments
bounds: endpoints within tol merge, every segment splits where another crosses
or touches it (the T-junction a partition makes), dangling edges are pruned,
and the half-edge walk turns to the next edge clockwise so every bounded face
comes out counter-clockwise. A piece nested inside a face of another piece is
a hole in it, so a ring of walls measures its body and a room with a column
measures its floor. Areas come from engineering.measure.polygon_area_perimeter,
the arithmetic analysis_measure_entity reports.

engineering/arch/rooms.py labels a room with the area of the face its point
lies in - a 4000 x 5000 room between 200 mm walls reads 20.00 m2, never the
axis area - and writes the room record onto the name text. Opening records
close door and window gaps along the wall faces, so two rooms either side of a
door stay two rooms. rooms_detect reads any plan's lines, drops faces under
min_area and thin wall bodies (mean width under 600 mm, a declared heuristic),
reports confidence 1.0 for faces enclosed only by our wall layer and 0.6
otherwise, lists arcs as skipped rather than flattening them, and never
modifies the drawing.

Two hardenings beyond the plan text, each with a test: read_records pages the
current space once and filters to the arch layers locally (the plan paged it
once per arch layer - twelve full scans, each a cross-process call per entity
on a live seat), keeping the same layer-then-drawing order; and an opening
record whose offset falls outside its wall (a stale record) is listed in
omitted instead of raising out of the read-only detector.

No new ActiveX member is called: both tools compose entity_list,
entity_get/set_xdata, layer_list and draw_prims, whose COM paths are already
live-verified.

SECTION 25 opens on this branch with arch_room and arch_rooms_detect under
the rooms marker; until Task 9 gives arch its group they file under
entity_creation and entity_query. Alias records, a regenerated inventory, the
README snapshot at 231 tools in 25 groups and the frozen group-size snapshot
follow.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

README.md

@@ -27,8 +27,8 @@ Live through COM on Windows, or headless through ezdxf anywhere — one typed co
 
 </div>
 
-> **v1.5 release snapshot:** 229 tools · 8 resources · 5 prompt templates · 4005 collected tests.
-> 229 is the **registered** count; a default install advertises 224 over `tools/list`,
+> **v1.5 release snapshot:** 231 tools · 8 resources · 5 prompt templates · 4005 collected tests.
+> 231 is the **registered** count; a default install advertises 226 over `tools/list`,
 > because `ENABLE_3D` is unset. `system_about` is the runtime authority.
 
 ## Why this exists
@@ -120,7 +120,7 @@ Claude Desktop, Cursor, or any stdio MCP host. For HTTP: `autocad-mcp --transpor
 | Quality loop | `drawing_preflight` → `drawing_plan` → `drawing_critique` → `drawing_refine` → `drawing_finalize` (0–100 score) |
 | Delivery | `drawing_deliver`: DXF/PDF/PNG + SHA-256 manifest + reopen-parity checks |
 
-<sub>229 tools in 25 groups; <code>TOOL_PACKS=core</code> hides the nine <code>pid_*</code> tools, the 22 environment tools and the 14 mechanical tools (<code>TOOL_PACKS=core,mech</code> keeps the last) from a client that needs none of them. Plus 8 resources that cost nothing in the tool budget (<code>autocad://drawing/info</code>, <code>layers</code>, <code>blocks</code>, <code>entities/stats</code>, <code>entities/{layer_name}</code>, <code>system/status</code>, <code>pid/symbols</code>, <code>standards/isa51</code>) and 5 prompt templates.</sub>
+<sub>231 tools in 25 groups; <code>TOOL_PACKS=core</code> hides the nine <code>pid_*</code> tools, the 22 environment tools and the 14 mechanical tools (<code>TOOL_PACKS=core,mech</code> keeps the last) from a client that needs none of them. Plus 8 resources that cost nothing in the tool budget (<code>autocad://drawing/info</code>, <code>layers</code>, <code>blocks</code>, <code>entities/stats</code>, <code>entities/{layer_name}</code>, <code>system/status</code>, <code>pid/symbols</code>, <code>standards/isa51</code>) and 5 prompt templates.</sub>
 
 **Two rules worth knowing.** Every coordinate in and out of a tool is WCS on both engines — the one exception is TEXT `rotation`, which stays in the entity frame because a mirrored TEXT is mirror-imaged and no scalar angle expresses that. And never read vertices back and shoelace them: that loses **28.2%** of the area on a semicircular edge, silently. `analysis_measure_entity(handle)` reads the real geometry and states its own accuracy.