chore: Clean up deprecated code and docs

- Move deprecated directories to src/_deprecated/:
  - hydration/ (old pipeline approach)
  - scraper-v2/ (old Puppeteer scraper)
  - canonical-hydration/ (merged into tasks)
  - Unused services: availability, crawler-logger, geolocation, etc
  - Unused utils: age-gate-playwright, HomepageValidator, stealthBrowser

- Archive outdated docs to docs/_archive/:
  - ANALYTICS_RUNBOOK.md
  - ANALYTICS_V2_EXAMPLES.md
  - BRAND_INTELLIGENCE_API.md
  - CRAWL_PIPELINE.md
  - TASK_WORKFLOW_2024-12-10.md
  - WORKER_TASK_ARCHITECTURE.md
  - ORGANIC_SCRAPING_GUIDE.md

- Add docs/CODEBASE_MAP.md as single source of truth
- Add warning files to deprecated/archived directories
- Slim down CLAUDE.md to essential rules only

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/docs/_archive/README.md

@@ -0,0 +1,25 @@
+# ARCHIVED DOCUMENTATION
+
+**WARNING: These docs may be outdated or inaccurate.**
+
+The code has evolved significantly. These docs are kept for historical reference only.
+
+## What to Use Instead
+
+**The single source of truth is:**
+- `CLAUDE.md` (root) - Essential rules and quick reference
+- `docs/CODEBASE_MAP.md` - Current file/directory reference
+
+## Why Archive?
+
+These docs were written during development iterations and may reference:
+- Old file paths that no longer exist
+- Deprecated approaches (hydration, scraper-v2)
+- APIs that have changed
+- Database schemas that evolved
+
+## If You Need Details
+
+1. First check CODEBASE_MAP.md for current file locations
+2. Then read the actual source code
+3. Only use archive docs as a last resort for historical context