feat: Auto-healing entry_point_discovery with browser-first transport

- Rewrote entry_point_discovery with auto-healing scheme:
  1. Check dutchie_discovery_locations for existing platform_location_id
  2. Browser-based GraphQL with 5x network retries
  3. Mark as needs_investigation on hard failure
- Browser (Puppeteer) is now DEFAULT transport - curl only when explicit
- Added migration 091 for tracking columns:
  - last_store_discovery_at: When store_discovery updated record
  - last_payload_at: When last product payload was saved
- Updated CODEBASE_MAP.md with transport rules documentation

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

backend/migrations/091_store_discovery_tracking.sql

@@ -0,0 +1,26 @@
+-- Migration 091: Add store discovery tracking columns
+-- Per auto-healing scheme (2025-12-12):
+-- Track when store_discovery last updated each dispensary
+-- Track when last payload was saved
+
+-- Add last_store_discovery_at to track when store_discovery updated this record
+ALTER TABLE dispensaries
+ADD COLUMN IF NOT EXISTS last_store_discovery_at TIMESTAMPTZ;
+
+-- Add last_payload_at to track when last product payload was saved
+-- (Complements last_fetch_at which tracks API fetch time)
+ALTER TABLE dispensaries
+ADD COLUMN IF NOT EXISTS last_payload_at TIMESTAMPTZ;
+
+-- Add index for finding stale discovery data
+CREATE INDEX IF NOT EXISTS idx_dispensaries_store_discovery_at
+ON dispensaries (last_store_discovery_at DESC NULLS LAST)
+WHERE crawl_enabled = true;
+
+-- Add index for finding dispensaries without recent payloads
+CREATE INDEX IF NOT EXISTS idx_dispensaries_payload_at
+ON dispensaries (last_payload_at DESC NULLS LAST)
+WHERE crawl_enabled = true;
+
+COMMENT ON COLUMN dispensaries.last_store_discovery_at IS 'When store_discovery task last updated this record';
+COMMENT ON COLUMN dispensaries.last_payload_at IS 'When last product payload was saved for this dispensary';