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- Archive outdated docs to docs/_archive/: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/src/_deprecated/DONT_USE.md

@@ -0,0 +1,46 @@
+# DEPRECATED CODE - DO NOT USE
+
+**These directories contain OLD, ABANDONED code.**
+
+## What's Here
+
+| Directory | What It Was | Why Deprecated |
+|-----------|-------------|----------------|
+| `hydration/` | Old pipeline for processing crawl data | Replaced by `src/tasks/handlers/` |
+| `scraper-v2/` | Old Puppeteer-based scraper engine | Replaced by curl-based `src/platforms/dutchie/client.ts` |
+| `canonical-hydration/` | Intermediate step toward canonical schema | Merged into task handlers |
+
+## What to Use Instead
+
+| Old (DONT USE) | New (USE THIS) |
+|----------------|----------------|
+| `hydration/normalizers/dutchie.ts` | `src/tasks/handlers/product-refresh.ts` |
+| `hydration/producer.ts` | `src/tasks/handlers/payload-fetch.ts` |
+| `scraper-v2/engine.ts` | `src/platforms/dutchie/client.ts` |
+| `scraper-v2/scheduler.ts` | `src/services/task-scheduler.ts` |
+
+## Why Keep This Code?
+
+- Historical reference only
+- Some patterns may be useful for debugging
+- Will be deleted once confirmed not needed
+
+## Claude Instructions
+
+**IF YOU ARE CLAUDE:**
+
+1. NEVER import from `src/_deprecated/`
+2. NEVER reference these files as examples
+3. NEVER try to "fix" or "update" code in here
+4. If you see imports from these directories, suggest replacing them
+
+**Correct imports:**
+```typescript
+// GOOD
+import { executeGraphQL } from '../platforms/dutchie/client';
+import { pool } from '../db/pool';
+
+// BAD - DO NOT USE
+import { something } from '../_deprecated/hydration/...';
+import { something } from '../_deprecated/scraper-v2/...';
+```