Add OAuth server implementation and Docker Compose configuration

- Introduced a new `compose.yaml` file to define the Docker service for the OAuth server.
- Created `oauth.py` to implement a single-user OAuth authorization server with PKCE, SQLite persistence, and token management.
- Added necessary database schema for OAuth clients, flows, codes, tokens, and login failures.
- Implemented login routes with CSRF protection and error handling.
- Updated `requirements.txt` to include dependencies for the OAuth server.

compose.yaml

@@ -0,0 +1,49 @@
+services:
+  dav-mcp:
+    build: .
+    restart: unless-stopped
+    read_only: true
+    tmpfs:
+      - /tmp
+    cap_drop:
+      - ALL
+    security_opt:
+      - no-new-privileges:true
+    ports:
+      - "${MCP_BIND_ADDRESS:-127.0.0.1}:${MCP_HOST_PORT:-8000}:8000"
+    environment:
+      WEBDAV_URL: ${WEBDAV_URL:-https://dav.ryankegel.com}
+      WEBDAV_ROOT: ${WEBDAV_ROOT:-/Notes/Personal}
+      WEBDAV_USERNAME: ${WEBDAV_USERNAME:?Set WEBDAV_USERNAME in .env}
+      WEBDAV_PASSWORD_FILE: /run/secrets/webdav_password
+      MCP_PUBLIC_URL: ${MCP_PUBLIC_URL:?Set MCP_PUBLIC_URL in .env}
+      MCP_ALLOWED_HOSTS: ${MCP_ALLOWED_HOSTS:?Set MCP_ALLOWED_HOSTS in .env}
+      MCP_ALLOWED_ORIGINS: ${MCP_ALLOWED_ORIGINS:-}
+      MCP_AUTH_USERNAME: ${MCP_AUTH_USERNAME:?Set MCP_AUTH_USERNAME in .env}
+      MCP_AUTH_PASSWORD_FILE: /run/secrets/mcp_auth_password
+      MCP_READ_ONLY: ${MCP_READ_ONLY:-true}
+      OAUTH_DATABASE_PATH: /data/oauth.sqlite3
+    secrets:
+      - webdav_password
+      - mcp_auth_password
+    volumes:
+      - oauth-data:/data
+    healthcheck:
+      test:
+        - CMD
+        - python
+        - -c
+        - "import urllib.request; urllib.request.urlopen('http://127.0.0.1:8000/healthz', timeout=2).read()"
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 20s
+
+secrets:
+  webdav_password:
+    file: ./secrets/webdav_password
+  mcp_auth_password:
+    file: ./secrets/mcp_auth_password
+
+volumes:
+  oauth-data: