feat(voyage): W2 impl (S4) — gate resolver model, adopt native effort:, doc-truth

S4 of the 2.1.181 upgrade — implementation, not a gate. TDD: failing test
written first for the resolver gate, then the fix; suite green throughout.

- Resolver MAJOR (FIX): lib/profiles/phase-signal-resolver.mjs now imports
  BASE_ALLOWED_MODELS from profile-validator and gates `model`
  (if 'model' in entry && BASE_ALLOWED_MODELS.includes(entry.model)),
  mirroring the EFFORT_LEVELS gate one line up. Out-of-allowlist models
  (gpt-4, haiku) are dropped instead of handed to an agent spawn —
  defense-in-depth behind brief-validator's validation-time check. No
  circular import (brief-validator already imports the same symbol).
  +2 tests (drops-invalid / keeps-valid).
- Native effort: (SHIP, static additive): effort: frontmatter on 8 agents —
  retrieval (task-finder, git-historian, dependency-tracer,
  architecture-mapper) = medium; adversarial-reasoning (plan-critic,
  risk-assessor, contrarian-researcher, review-coordinator) = high. The
  other 15 stay unset -> inherit Opus-4.8 default (high). This per-spawn
  REASONING effort is a different axis from brief phase_signals.effort
  (ORCHESTRATION shape) per the S3 decision.
- Doc-truth + axis distinction: new canonical docs/profiles.md
  §Model & effort axes (opus->Opus 4.8 default-high; orchestration vs
  reasoning effort table; native-effort precedence; per-agent levels).
  Short notes in CLAUDE.md (after Agents table) and README.md (Cost
  profile), both pointing to profiles.md.
- Open (non-blocking, unchanged): only STATIC effort shipped — the
  verified-safe minimum. Profile-driven DYNAMIC effort still needs
  verification of the per-spawn effort param or env-var injection.

Matrix: new "S4 resolutions" section. Tests 582 total / 580 pass / 0 fail /
2 skip (was 578 pass; +2). claude plugin validate passes (only pre-existing
root-CLAUDE.md warning).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LqBYc8Ltrk7LipyJmGxXiB

agents/architecture-mapper.md

@@ -22,6 +22,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: medium
 color: cyan
 tools: ["Read", "Glob", "Grep", "Bash"]
 ---

agents/contrarian-researcher.md

@@ -25,6 +25,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: high
 color: red
 tools: ["WebSearch", "WebFetch", "mcp__tavily__tavily_search", "mcp__tavily__tavily_research"]
 ---

agents/dependency-tracer.md

@@ -22,6 +22,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: medium
 color: blue
 tools: ["Read", "Glob", "Grep", "Bash"]
 ---

agents/git-historian.md

@@ -22,6 +22,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: medium
 color: yellow
 tools: ["Bash", "Read", "Glob", "Grep"]
 ---

agents/plan-critic.md

@@ -22,6 +22,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: high
 color: red
 tools: ["Read", "Glob", "Grep"]
 ---

agents/review-coordinator.md

@@ -7,6 +7,7 @@ description: |
   Judge filters, Cloudflare reasonableness filter, verdict computation.
   Synthesis-level inference across files is forbidden in v1.0.
 model: opus
+effort: high
 color: yellow
 tools: ["Read", "Glob", "Grep"]
 ---

agents/risk-assessor.md

@@ -22,6 +22,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: high
 color: yellow
 tools: ["Read", "Glob", "Grep", "Bash"]
 ---

agents/task-finder.md

@@ -23,6 +23,7 @@ description: |
   </commentary>
   </example>
 model: opus
+effort: medium
 color: green
 tools: ["Read", "Glob", "Grep", "Bash"]
 ---