feat(server): settings pack — 22 environment tools behind TOOL_PACKS, lean grows to 55, three groups, golden set +10

Task 24 (merge sanity) on main after the five track E groups merged.

- TOOL_PACK_NAMES = ("core", "pid", "settings"); PACK_TOOL_NAMES["settings"]
  is exactly the 22 SECTION 20 tools. Styles and page setup stay in core.
- LEAN_TOOL_NAMES += page_setup_apply, batch_plot (53 -> 55).
- _GROUP_TAG_PRIORITY / _GROUP_TAG_LABELS: "style" moved up next to "pid",
  "pagesetup" -> page_setup and "environment" -> environment added; the 28
  SECTION 19/20 decorators gain their section tag, so _tool_groups() reports
  styles 10 / page_setup 6 / environment 22 (23 groups, 204 tools) and
  pack == group == section for the settings pack.
- SECTION headers, backends/base.py composition, contracts/__init__.py
  exports and the layer_states feature entry were already correct after the
  merge (read and confirmed, nothing edited).
- Pack text: config.py, .env.example, README config row; README <sub> line
  204 tools in 23 groups; release snapshot 3259 collected tests (measured).
- docs/tool-inventory.json regenerated; registry snapshot re-derived.
- tests: test_tool_packs.py replaced (11 tests), test_capability_contract.py
  +3 (composition, the agreed capability flags, layer_states honesty),
  golden set +10 tuning cases (81 = 66 tuning + 15 holdout); all ten route
  in the top 3 without alias edits.

Deviation from the plan text: TRACK_E_KEYS carries five keys, not six. The
plan's "mleaderstyle" (ezdxf True / com False) contradicts spec §8.1, which
retracted that key because the ActiveX route exists (§4.2); measured on the
tree: capability_keys() == {boundary_trace, chspace, interactive_prompt,
live_application, preferences, revcloud, wipeout}, and
ComBackend.mleaderstyle_create is a native implementation
(backends/com_backend.py:6752, is_capability_default -> False). The test now
also asserts the key is absent.

No new ActiveX call was written in this task, so no live probe was needed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

README.md

@@ -27,7 +27,7 @@ Live through COM on Windows, or headless through ezdxf anywhere — one typed co
 
 </div>
 
-> **v1.5 release snapshot:** 204 tools · 8 resources · 5 prompt templates · 2423 collected tests.
+> **v1.5 release snapshot:** 204 tools · 8 resources · 5 prompt templates · 3259 collected tests.
 > 204 is the **registered** count; a default install advertises 199 over `tools/list`,
 > because `ENABLE_3D` is unset. `system_about` is the runtime authority.
 
@@ -115,7 +115,7 @@ 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>172 tools in 20 groups; <code>TOOL_PACKS=core</code> hides the nine <code>pid_*</code> tools from a client that never draws a P&ID. 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>204 tools in 23 groups; <code>TOOL_PACKS=core</code> hides the nine <code>pid_*</code> tools and the 22 environment tools (<code>TOOL_PACKS=core,settings</code> keeps the latter) from a client that needs neither. 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.
 
@@ -217,7 +217,7 @@ Nothing loads a `.env` file — export these, or set them in your MCP client's `
 | `AUTOCAD_MCP_BACKEND` | `auto` | `auto`, `com`, or `ezdxf` |
 | `CAD_PROGID` | `AutoCAD.Application` | COM ProgID the live backend attaches to |
 | `TOOL_PROFILE` | `full` | `lean` (50 curated tools) or `full` |
-| `TOOL_PACKS` | `all` | Vertical packs to advertise: `core,pid` (`core` always on) |
+| `TOOL_PACKS` | `all` | Vertical packs to advertise: `core,pid,settings` (`core` always on) |
 | `DISCOVERY_MODE` | `off` | `search` replaces the catalog with `search_tools` + `call_tool` |
 | `ENABLE_3D` | `false` | Expose the opt-in `solid_*` tools (COM) |
 | `LOG_LEVEL` | `INFO` | Python logging level |