Initial commit: cert-manager API server

FastAPI-based SSL certificate automation server.
- Google Public CA wildcard cert issuance via certbot
- Cloudflare DNS-01 challenge with auto EAB key generation
- APISIX multi-instance deployment with domain-instance mapping
- Vault integration for all secrets
- Bearer token auth, retry logic, Discord DM alerts
- Auto-renewal scheduler (daily 03:00 UTC)

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

docker-compose.yml

@@ -0,0 +1,15 @@
+services:
+  cert-manager:
+    build: .
+    container_name: cert-manager
+    restart: unless-stopped
+    ports:
+      - "8000:8000"
+    volumes:
+      - ./data/certbot:/data/certbot
+      - ./config.json:/data/config/config.json:ro
+    env_file:
+      - .env
+    environment:
+      - TZ=UTC
+      - VAULT_ADDR=https://vault.inouter.com