merge: track H group N

The merge agent stopped this branch on an add/add conflict it had not been
told to expect: groups U and N each created tests/test_understand_tools.py.
Resolved by hand:
- tests/test_understand_tools.py stays U's (the drawing_understand wire
  tests), and N's takeoff wire tests move whole to
  tests/test_understand_takeoff_tools.py. Each file keeps its own client
  fixture: U's opens a fresh document, N's reads files only.
- server.py: SECTION 26 (4 tools, U then D) is kept as merged, and SECTION
  27 (Plant Takeoffs, 2 tools) follows it whole, above the RESOURCES
  banner.
- discovery/aliases.py: additive; the two takeoff records follow the four
  readers.
- tests/test_tool_registry.py: all three branches' paragraphs are kept.
  The snapshot is recomputed from the live registry: analysis 18, 247
  tools. Task 11 ranks `understand` and `plant`.
- docs/tool-inventory.json regenerated (247 tools, 26 groups); README
  counts are 247 registered / 242 advertised. The collected-tests figure
  is left to Task 11.

ruff check passes. Suite: 4919 passed, 1 xfailed. The one deselected test
is the collected-tests figure.

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:** 245 tools · 8 resources · 5 prompt templates · 4516 collected tests.
-> 245 is the **registered** count; a default install advertises 240 over `tools/list`,
+> **v1.5 release snapshot:** 247 tools · 8 resources · 5 prompt templates · 4516 collected tests.
+> 247 is the **registered** count; a default install advertises 242 over `tools/list`,
 > because `ENABLE_3D` is unset. `system_about` is the runtime authority.
 
 ## Why this exists
@@ -122,7 +122,7 @@ 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>245 tools in 26 groups; <code>TOOL_PACKS=core</code> hides the nine <code>pid_*</code> tools, the 22 environment tools, the 14 mechanical tools and the 12 architectural tools (<code>TOOL_PACKS=core,mech</code> keeps the mechanical ones, <code>TOOL_PACKS=core,arch</code> the architectural ones) 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>247 tools in 26 groups; <code>TOOL_PACKS=core</code> hides the nine <code>pid_*</code> tools, the 22 environment tools, the 14 mechanical tools and the 12 architectural tools (<code>TOOL_PACKS=core,mech</code> keeps the mechanical ones, <code>TOOL_PACKS=core,arch</code> the architectural ones) 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.