release: 1.6.0

The v1.6 roadmap in five tracks: 154 -> 247 registered tools in 28 groups.

Evidence re-measured for the release:
- correctness A/B against v1.5.1: 26/48 -> 48/48, 22 fixed, 0 regressed
  (ab-v1.5.1-vs-v1.6.0.json, replacing the -dev report);
- the reference adapter on matrix v7: 21/21 (autocad-mcp-pro.json, which
  was the v3 run of 1.5); the published-report test follows it to v7;
- the 100-point rubric re-scored per category, every withheld point named:
  93 (the competitor rows are their July snapshots, not re-reviewed);
- the perf lane as medians of five alternating runs, beside a v1.4.0
  comparison on one interpreter (perf-v1.4.0-vs-v1.6.0.json).

Two roadmap criteria are not green, and the changelog, the README and the
roadmap say so: criterion 5 is withdrawn (track D, Plant 3D, dropped) and
criterion 7 is not met (creation 1.25x / 1.38x v1.4.0's time, still
1.17x / 1.20x with the timeout off). Carried to 1.7.

README rewritten for 1.6: what is new, the mechanical and architectural
sheets, the rubric and task-matrix charts, the measured limits (including
the four feature tables that ship empty), and the 1.7 roadmap. server.json
describes the 1.6 surface and declares TOOL_PACKS. CLAUDE.md corrects the
ISO 286 letter set and the empty feature tables.

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

scripts/check_doc_numbers.py

@@ -29,9 +29,9 @@ ROOT = Path(__file__).resolve().parents[1]
 
 #: The published A/B report the README and benchmarks/README quote. Bump this,
 #: the two row labels below and the prose together, or the gate reports drift.
-AB_REPORT = "benchmarks/results/published/ab-v1.5.1-vs-v1.6.0-dev.json"
+AB_REPORT = "benchmarks/results/published/ab-v1.5.1-vs-v1.6.0.json"
 AB_BASELINE_LABEL = r"v1\.5\.1"
-AB_CURRENT_LABEL = r"v1\.6\.0-dev"
+AB_CURRENT_LABEL = r"v1\.6\.0"
 
 
 def _read(relative: str) -> str:
@@ -160,7 +160,7 @@ CHECKS: list[tuple[str, str, str, str]] = [
         "README.md",
         "A/B fixed count",
         AB_CURRENT_LABEL
-        + r"\*\* \*\(this branch\)\* \| \*\*\d+ / \d+\*\* \| \*\*\d+ %\*\* \| (\d+)",
+        + r"\*\* \*\(this release\)\* \| \*\*\d+ / \d+\*\* \| \*\*\d+ %\*\* \| (\d+)",
         "ab_fixed",
     ),
     (
@@ -172,7 +172,7 @@ CHECKS: list[tuple[str, str, str, str]] = [
     (
         "benchmarks/README.md",
         "A/B fixed count",
-        r"\*\*" + AB_CURRENT_LABEL + r"\*\* \(this branch\) \| \d+ / \d+ \| \d+ % \| (\d+)",
+        r"\*\*" + AB_CURRENT_LABEL + r"\*\* \(this release\) \| \d+ / \d+ \| \d+ % \| (\d+)",
         "ab_fixed",
     ),
     ("CLAUDE.md", "A/B suite size", r"correctness_suite\.py` \((\d+) checks\)", "ab_total"),