feat(plugins): implement Sprint 4 commands (#241-#258)

Sprint 4 - Plugin Commands implementation adding 18 new user-facing
commands across 8 plugins as part of V5.2.0 Plugin Enhancements.

**projman:**
- #241: /sprint-diagram - Mermaid visualization of sprint issues

**pr-review:**
- #242: Confidence threshold config (PR_REVIEW_CONFIDENCE_THRESHOLD)
- #243: /pr-diff - Formatted diff with inline review comments

**data-platform:**
- #244: /data-quality - DataFrame quality checks (nulls, duplicates, outliers)
- #245: /lineage-viz - dbt lineage as Mermaid diagrams
- #246: /dbt-test - Formatted dbt test runner

**viz-platform:**
- #247: /chart-export - Export charts to PNG/SVG/PDF via kaleido
- #248: /accessibility-check - Color blind validation (WCAG contrast)
- #249: /breakpoints - Responsive layout configuration

**contract-validator:**
- #250: /dependency-graph - Plugin dependency visualization

**doc-guardian:**
- #251: /changelog-gen - Generate changelog from conventional commits
- #252: /doc-coverage - Documentation coverage metrics
- #253: /stale-docs - Flag outdated documentation

**claude-config-maintainer:**
- #254: /config-diff - Track CLAUDE.md changes over time
- #255: /config-lint - 31 lint rules for CLAUDE.md best practices

**cmdb-assistant:**
- #256: /cmdb-topology - Infrastructure topology diagrams
- #257: /change-audit - NetBox audit trail queries
- #258: /ip-conflicts - Detect IP conflicts and overlaps

Closes #241, #242, #243, #244, #245, #246, #247, #248, #249,
#250, #251, #252, #253, #254, #255, #256, #257, #258

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/doc-guardian/commands/stale-docs.md

@@ -0,0 +1,143 @@
+---
+description: Detect documentation files that are stale relative to their associated code
+---
+
+# Stale Documentation Detection
+
+Identify documentation files that may be outdated based on commit history.
+
+## Process
+
+1. **Map Documentation to Code**
+   Build relationships between docs and code:
+
+   | Doc File | Related Code |
+   |----------|--------------|
+   | README.md | All files in same directory |
+   | API.md | src/api/**/* |
+   | CLAUDE.md | Configuration files, scripts |
+   | docs/module.md | src/module/**/* |
+   | Component.md | Component.tsx, Component.css |
+
+2. **Analyze Commit History**
+   For each doc file:
+   - Find last commit that modified the doc
+   - Find last commit that modified related code
+   - Count commits to code since doc was updated
+
+3. **Calculate Staleness**
+   ```
+   Commits Behind = Code Commits Since Doc Update
+   Days Behind = Days Since Doc Update - Days Since Code Update
+   ```
+
+4. **Apply Threshold**
+   Default: Flag if documentation is 10+ commits behind related code
+
+   **Staleness Levels:**
+   | Commits Behind | Level | Action |
+   |----------------|-------|--------|
+   | 0-5 | Fresh | No action needed |
+   | 6-10 | Aging | Review recommended |
+   | 11-20 | Stale | Update needed |
+   | 20+ | Critical | Immediate attention |
+
+5. **Output Format**
+```
+## Stale Documentation Report
+
+### Critical (20+ commits behind)
+| File | Last Updated | Commits Behind | Related Code |
+|------|--------------|----------------|--------------|
+| docs/api.md | 2024-01-15 | 34 | src/api/**/* |
+
+### Stale (11-20 commits behind)
+| File | Last Updated | Commits Behind | Related Code |
+|------|--------------|----------------|--------------|
+| README.md | 2024-02-20 | 15 | package.json, src/index.ts |
+
+### Aging (6-10 commits behind)
+| File | Last Updated | Commits Behind | Related Code |
+|------|--------------|----------------|--------------|
+| CONTRIBUTING.md | 2024-03-01 | 8 | .github/*, scripts/* |
+
+### Summary
+- Critical: 1 file
+- Stale: 1 file
+- Aging: 1 file
+- Fresh: 12 files
+- Total documentation files: 15
+```
+
+## Options
+
+| Flag | Description | Default |
+|------|-------------|---------|
+| `--threshold <n>` | Commits behind to flag as stale | 10 |
+| `--days` | Use days instead of commits | false |
+| `--path <dir>` | Scan specific directory | Project root |
+| `--doc-pattern <glob>` | Pattern for doc files | `**/*.md,**/README*` |
+| `--ignore <glob>` | Ignore specific docs | `CHANGELOG.md,LICENSE` |
+| `--show-fresh` | Include fresh docs in output | false |
+| `--format <fmt>` | Output format (table, json) | table |
+
+## Relationship Detection
+
+How docs are mapped to code:
+
+1. **Same Directory**
+   - `src/api/README.md` relates to `src/api/**/*`
+
+2. **Name Matching**
+   - `docs/auth.md` relates to `**/auth.*`, `**/auth/**`
+
+3. **Explicit Links**
+   - Parse `[link](path)` in docs to find related files
+
+4. **Import Analysis**
+   - Track which modules are referenced in code examples
+
+## Configuration
+
+Create `.doc-guardian.yml` to customize mappings:
+```yaml
+stale-docs:
+  threshold: 10
+  mappings:
+    - doc: docs/deployment.md
+      code:
+        - Dockerfile
+        - docker-compose.yml
+        - .github/workflows/deploy.yml
+    - doc: ARCHITECTURE.md
+      code:
+        - src/**/*
+  ignore:
+    - CHANGELOG.md
+    - LICENSE
+    - vendor/**
+```
+
+## Example Usage
+
+```
+/stale-docs
+/stale-docs --threshold 5
+/stale-docs --days --threshold 30
+/stale-docs --path docs/ --show-fresh
+```
+
+## Integration with doc-audit
+
+`/stale-docs` focuses specifically on commit-based staleness, while `/doc-audit` checks content accuracy. Use both for comprehensive documentation health:
+
+```
+/doc-audit      # Check for broken references and content drift
+/stale-docs     # Check for files that may need review
+```
+
+## Exit Codes
+
+- 0: No critical or stale documentation
+- 1: Stale documentation found (useful for CI)
+- 2: Critical documentation found