Add RAG semantic search and proactive event notifications

Implement hybrid knowledge search using Cloudflare Vectorize + Workers AI
embeddings (bge-base-en-v1.5, 768d) merged with existing D1 LIKE queries,
with graceful degradation when Vectorize is unavailable. Add admin API
endpoints for batch/single article indexing.

Add 4 proactive notification cron jobs: server status changes, deposit
confirmation/rejection alerts, pending payment reminders (1h+), and bank
deposit matching notifications — all with DB-column-based deduplication.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

wrangler.toml

@@ -45,6 +45,12 @@ bucket_name = "ai-support-assets"
 binding = "CLOUD_ORCHESTRATOR"
 service = "cloud-orchestrator"
 
+# Vectorize (RAG semantic search)
+# Create index: npx wrangler vectorize create knowledge-embeddings --dimensions=768 --metric=cosine
+[[vectorize]]
+binding = "VECTORIZE"
+index_name = "knowledge-embeddings"
+
 # Cron Triggers:
 # - 매일 자정(KST): 만료 알림 + 데이터 아카이빙 + 정합성 검증
 # - 매 5분: pending 상태 자동 정리