feat: home-gateway 초기 구성 — Mac mini에서 GPU 서버로 전면 이전

OrbStack 라이선스 만료로 Mac mini Docker 서비스를 GPU 서버로 통합.
nginx → Caddy 전환, 12개 서브도메인 자동 HTTPS, fail2ban Caddy JSON 연동.

주요 변경:
- home-caddy: Caddy 리버스 프록시 (Let's Encrypt 자동 HTTPS)
- home-fail2ban: Caddy JSON 로그 기반 보안 모니터링
- home-ddns: Cloudflare DDNS (API 키 .env 분리)
- gpu-hub-api/web: AI 백엔드 라우터 + 웹 UI (gpu-services에서 이전)
- AI 런타임(Ollama) 내부망 전용, 외부는 gpu-hub 인증 게이트웨이 경유

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hub-api/db/database.py

@@ -0,0 +1,50 @@
+import aiosqlite
+
+from config import settings
+
+SCHEMA = """
+CREATE TABLE IF NOT EXISTS chat_sessions (
+    id TEXT PRIMARY KEY,
+    title TEXT,
+    model TEXT NOT NULL,
+    role TEXT NOT NULL DEFAULT 'guest',
+    created_at REAL NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS chat_messages (
+    id TEXT PRIMARY KEY,
+    session_id TEXT NOT NULL REFERENCES chat_sessions(id),
+    role TEXT NOT NULL,
+    content TEXT NOT NULL,
+    created_at REAL NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS usage_logs (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    backend_id TEXT NOT NULL,
+    model TEXT NOT NULL,
+    prompt_tokens INTEGER DEFAULT 0,
+    completion_tokens INTEGER DEFAULT 0,
+    latency_ms REAL DEFAULT 0,
+    user_role TEXT NOT NULL DEFAULT 'guest',
+    created_at REAL NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_messages_session ON chat_messages(session_id);
+CREATE INDEX IF NOT EXISTS idx_usage_created ON usage_logs(created_at);
+"""
+
+
+async def init_db():
+    """Initialize SQLite database with WAL mode and schema."""
+    async with aiosqlite.connect(settings.db_path) as db:
+        await db.execute("PRAGMA journal_mode=WAL")
+        await db.executescript(SCHEMA)
+        await db.commit()
+
+
+async def get_db() -> aiosqlite.Connection:
+    """Get a database connection."""
+    db = await aiosqlite.connect(settings.db_path)
+    await db.execute("PRAGMA journal_mode=WAL")
+    return db