docs: enhance 5 thin commands and add Rust API example

Commands enhanced with multi-language support, error recovery strategies,
and structured step-by-step workflows:
- build-fix: build system detection table, fix loop, recovery strategies
- test-coverage: framework detection, test generation rules, before/after report
- refactor-clean: safety tiers (SAFE/CAUTION/DANGER), multi-language tools
- update-codemaps: codemap format spec, diff detection, metadata headers
- update-docs: source-of-truth mapping, staleness checks, generated markers

New example:
- rust-api-CLAUDE.md: Axum + SQLx + PostgreSQL with layered architecture,
  thiserror patterns, compile-time SQL verification, integration test examples

commands/build-fix.md

@@ -1,29 +1,62 @@
 # Build and Fix
 
-Incrementally fix TypeScript and build errors:
+Incrementally fix build and type errors with minimal, safe changes.
 
-1. Run build: npm run build or pnpm build
+## Step 1: Detect Build System
 
-2. Parse error output:
-   - Group by file
-   - Sort by severity
+Identify the project's build tool and run the build:
 
-3. For each error:
-   - Show error context (5 lines before/after)
-   - Explain the issue
-   - Propose fix
-   - Apply fix
-   - Re-run build
-   - Verify error resolved
+| Indicator | Build Command |
+|-----------|---------------|
+| `package.json` with `build` script | `npm run build` or `pnpm build` |
+| `tsconfig.json` (TypeScript only) | `npx tsc --noEmit` |
+| `Cargo.toml` | `cargo build 2>&1` |
+| `pom.xml` | `mvn compile` |
+| `build.gradle` | `./gradlew compileJava` |
+| `go.mod` | `go build ./...` |
+| `pyproject.toml` | `python -m py_compile` or `mypy .` |
 
-4. Stop if:
-   - Fix introduces new errors
-   - Same error persists after 3 attempts
-   - User requests pause
+## Step 2: Parse and Group Errors
 
-5. Show summary:
-   - Errors fixed
-   - Errors remaining
-   - New errors introduced
+1. Run the build command and capture stderr
+2. Group errors by file path
+3. Sort by dependency order (fix imports/types before logic errors)
+4. Count total errors for progress tracking
 
-Fix one error at a time for safety!
+## Step 3: Fix Loop (One Error at a Time)
+
+For each error:
+
+1. **Read the file** — Use Read tool to see error context (10 lines around the error)
+2. **Diagnose** — Identify root cause (missing import, wrong type, syntax error)
+3. **Fix minimally** — Use Edit tool for the smallest change that resolves the error
+4. **Re-run build** — Verify the error is gone and no new errors introduced
+5. **Move to next** — Continue with remaining errors
+
+## Step 4: Guardrails
+
+Stop and ask the user if:
+- A fix introduces **more errors than it resolves**
+- The **same error persists after 3 attempts** (likely a deeper issue)
+- The fix requires **architectural changes** (not just a build fix)
+- Build errors stem from **missing dependencies** (need `npm install`, `cargo add`, etc.)
+
+## Step 5: Summary
+
+Show results:
+- Errors fixed (with file paths)
+- Errors remaining (if any)
+- New errors introduced (should be zero)
+- Suggested next steps for unresolved issues
+
+## Recovery Strategies
+
+| Situation | Action |
+|-----------|--------|
+| Missing module/import | Check if package is installed; suggest install command |
+| Type mismatch | Read both type definitions; fix the narrower type |
+| Circular dependency | Identify cycle with import graph; suggest extraction |
+| Version conflict | Check `package.json` / `Cargo.toml` for version constraints |
+| Build tool misconfiguration | Read config file; compare with working defaults |
+
+Fix one error at a time for safety. Prefer minimal diffs over refactoring.