fix(docs): add spec-scanner page and model-routing to nav

Fixes docs deploy failure after v5.1.0:
- Creates docs/agents/spec-scanner.md (was linked from agents/index.md
  but missing, which failed mkdocs strict mode)
- Adds Scanner to agents nav
- Adds Model Routing to advanced nav

Author: Habib0x0

docs/agents/spec-scanner.md

@@ -0,0 +1,36 @@
+# spec-scanner
+
+The spec-scanner analyzes an existing codebase and produces a **project profile** — a structured summary of the tech stack, detected patterns, domain entities, and registration points. Other agents read this profile to generate wiring-aware specs and code.
+
+## Role
+
+Scan the codebase on first `/spec` invocation (Phase 0), detect what the project is built on, and record that intelligence in `.claude/specs/_project-profile.md` (or split files for large monorepos). The profile lives in the repo and is reused by subsequent agents.
+
+## Model
+
+**sonnet tier.** The scanner reads many files and extracts structural information. Depth of reasoning matters less than throughput — the sonnet tier is the right fit for fast, accurate pattern detection.
+
+## When It Runs
+
+- `/spec <name>` — Phase 0 auto-scan on first invocation if no profile exists
+- `/spec-scan` — manual rescan to refresh the profile after significant codebase changes
+
+## What It Records
+
+The project profile captures six sections:
+
+1. **Stack** — Framework, language, backend, database, styling system.
+2. **Patterns** — Detected conventions with confidence levels (high/medium/low). The planner and tasker prefer high-confidence patterns when generating specs.
+3. **Entity Registry** — Domain entities and their CRUD implementation status, used for gap analysis during requirements.
+4. **Registration Points** — Specific `file:line` locations where new artifacts (routes, components, migrations) must be registered so the implementer doesn't produce orphaned code.
+5. **Regression Markers** — Prior bug fixes and the files they touched, so reviewers know which areas are regression-prone.
+6. **Manual Overrides** — User-editable section preserved across rescans.
+
+Output: `.claude/specs/_project-profile.md` (single-file) or `_profile-index.md` + `_profile-<domain>.md` files (split for large monorepos).
+
+## Key Rules
+
+- Never reads credential-bearing files (`.env`, `~/.aws`, `~/.ssh`, etc.). The scanner has an explicit skip list.
+- Confidence levels on patterns are not guesses — they reflect how consistently the pattern appears in the scanned code.
+- The Manual Overrides section is preserved across rescans. Users can pin conventions that the scanner can't detect automatically.
+- For large codebases, the scanner splits the profile by domain to keep each file readable.

mkdocs.yml

@@ -91,6 +91,7 @@ nav:
     - Consultant: agents/spec-consultant.md
     - Acceptor: agents/spec-acceptor.md
     - Documenter: agents/spec-documenter.md
+    - Scanner: agents/spec-scanner.md
   - Reference:
     - EARS Notation: reference/ears-notation.md
     - Design Patterns: reference/design-patterns.md
@@ -101,5 +102,6 @@ nav:
     - Crash Recovery: advanced/crash-recovery.md
     - Cross-Spec Dependencies: advanced/cross-spec-deps.md
     - CI/CD Integration: advanced/ci-cd.md
+    - Model Routing: advanced/model-routing.md
     - Extending the Plugin: advanced/extending.md
   - Privacy Policy: privacy.md