feat: direct subscription fetching, URI parser, FLClashX compatibility

- Fetch subscriptions directly via httpx (mihomo UA → YAML, xray-checker → base64 URI list)
- Add uri_parser.py: vless/vmess/ss/trojan/hysteria2 URI → Mihomo proxy dicts
- Fix YAML quoting for Go parser (strings starting with special chars)
- Remove hidden:true and proxy-providers from delivered configs
- Inject all service groups into GLOBAL proxies for FLClashX group discovery
- Strip placeholder proxy-providers (e.g. "subscription") not in DB
- Fix Mihomo healthcheck: add Bearer auth header
- Add README

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

docker-compose.yml

@@ -15,7 +15,7 @@ services:
       - proxy_net
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "wget", "-q", "-O-", "http://localhost:9090/version"]
+      test: ["CMD", "wget", "-q", "-O-", "--header=Authorization: Bearer changeme", "http://localhost:9090/version"]
       interval: 5s
       timeout: 3s
       retries: 12