v1.16.0

Downstream-driven round: ArchCanvas's archlang-1.15 adoption surfaced two upstream gaps its own
ship gate + topology fixer had already filled locally, so those capabilities move upstream as
advisory data and the generated agent docs are re-pointed to teach the v1.13 placement sugar
where models actually imitate it — the worked examples. Core stays zero runtime dependencies; the
default SVG output is byte-identical throughout.

Added

• suggestTopology gains two connectivity-fault kinds — Suggestion.code widens 2 → 4 to
  W_ROOM_UNREACHABLE | W_BEDROOM_NO_WINDOW | W_NO_ENTRANCE | W_BATH_VIA_BEDROOM. Both new builders
  are ported from capabilities proven in ArchCanvas's production topology fixer and each mirrors the
  semantics of the matching arch lint rule so a suggestion fires iff the lint fires:

  • W_NO_ENTRANCE — fires when the plan has an exterior wall but no entrance
    (access.hasEntrance === false). Emits door on <wall> at <pct>% width 900 candidates on the
    longest opening-free exterior run of an entrance-suitable room (not a bedroom, not a wet room),
    falling back to the remaining rooms only when no suitable room touches an exterior wall; the
    rationale names the room and that this creates the building's entrance.
  • W_BATH_VIA_BEDROOM — reuses the two-BFS pattern from the reachability lint (reach-all vs
    reach-excluding-bedrooms) to find a wet room reachable only through a bedroom, and suggests a
    door onto a neighbour that itself has a bedroom-free route (non-bedroom neighbours preferred over
    an exterior-wall fallback regardless of run length — reconnecting to circulation is the real fix).
    One suggestion per affected wet room.

  Both stay ADR 0005-compliant (facts and lint, not an architect):
  deterministic, closed-form, data-only, fail-open ([] on ambiguity or a resolve error), ordered by
  the existing free-run-length → wall-id → position tie-break, top 3 — never applied.

• Furniture-aware door candidates. For door candidates only, the blocked-span computation now
  also subtracts wall runs where a furniture footprint intrudes into the door's approach corridor — the
  strip inside the target room along that wall, APPROACH_DEPTH = 900 mm deep — so a suggested door
  never opens straight onto a piece. Windows are exempt (furniture under a window is normal). The three
  door builders (W_NO_ENTRANCE, W_ROOM_UNREACHABLE, W_BATH_VIA_BEDROOM) feed the furniture-blocked
  runs into longestFreeRun; the window builder is unchanged. Fail-open — a furniture-free plan yields
  no blocked runs, so every pinned golden (all furniture-free fixtures) stays byte-identical.

Changed

• The generated agent spec now teaches attachment-first through its worked example.
  scripts/gen-llm-spec.ts's SPEC_EXAMPLES swaps the coordinate-math studio.arch for the
  attachment/strip/anchor attached.arch as the flagship worked example (parametric.arch stays second
  as the sanctioned computed-at idiom); neither examples/*.arch file changed. The ## Common mistakes table is rewritten from coordinate fixes to attachment-first guidance (off-wall opening →
  on <wall> at <pos>, hosted by construction; hand-summed room offsets → strip; a guessed furniture
  at → in <room> anchor <9-point>), keeping the genuinely universal rows (mm units, +y down, unique
  ids). The fix-topology prose now names all four suggest kinds and leads with arch suggest --json.
  spec.llm.md regenerated (~15.9 → ~14.8 KB; llms-full.txt regenerated in the same chain).
• SKILL.md anchor grammar corrected. The stale anchor <corner|edge> placeholder becomes the real
  nine-point token list (top-left, top, top-right, left, center, right, bottom-left, bottom, bottom-right),
  and the topology section names all four suggest faults and notes the candidates are furniture-aware.
• CLI / MCP prose lists all four suggest kinds. The arch suggest usage line (src/cli.ts), the
  cmdSuggest doc comment (src/cli/commands-author.ts), and the MCP suggest tool description
  (packages/mcp/src/server.ts) now name unreachable / no-entrance / bath-via-bedroom / windowless-bedroom
  and note the attachment form + furniture-awareness. No wiring change — the raw Suggestion[] passes
  through untouched. The MCP shim republishes as @chanmeng666/archlang-mcp@0.2.1 (version-bump-only
  release so the refreshed tool description actually reaches npm and the MCP registry — the release
  workflow's idempotency guard would have skipped an unbumped 0.2.0).
• suggestTopology's pre-existing W_ROOM_UNREACHABLE builder is now gated on the plan having an
  entrance. An entrance-less plan previously produced per-room W_ROOM_UNREACHABLE suggestions; it now
  yields the single W_NO_ENTRANCE suggestion instead, matching the lint's own suppression behavior (the
  reachability rule reports no-entrance, not per-room unreachability, when there is no way in). No pinned
  golden is affected — the existing faulty fixture has an entrance.
• Note (eval baseline): spec.llm.md is the eval's author prompt, and this change replaces a worked
  example in it, so it now differs from the prompt behind the calibrated live baseline. No scoring/judge/fixture
  code changed; re-running the paid live baseline under the new prompt stays a separate, owner-approved action
  (default: not run).