feat: add stdio transport support for local MCP usage

Add a lightweight stdio transport path so users can run the server
locally with MCP clients like Claude Code using `uvx nextcloud-mcp-server run`.

- New `nextcloud_mcp_server/stdio.py` with minimal FastMCP setup for
  single-user BasicAuth (no OAuth, semantic search, or background sync)
- Default transport changed from streamable-http to stdio
- Dockerfile updated to explicitly use streamable-http for containers
- CLI `--enable-app` now includes news, collectives, and sharing
- README Quick Start section with uvx and MCP client config examples

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

README.md

@@ -15,7 +15,39 @@ This is a **dedicated standalone MCP server** designed for external MCP clients
 > [!NOTE]
 > **Looking for AI features inside Nextcloud?** Nextcloud also provides [Context Agent](https://github.com/nextcloud/context_agent), which powers the Assistant app and runs as an ExApp inside Nextcloud. See [docs/comparison-context-agent.md](docs/comparison-context-agent.md) for a detailed comparison of use cases.
 
-## Quick Start (Docker)
+## Quick Start
+
+Run the server locally with [uvx](https://docs.astral.sh/uv/) (no installation required):
+
+```bash
+NEXTCLOUD_HOST=https://your.nextcloud.instance.com \
+NEXTCLOUD_USERNAME=your_username \
+NEXTCLOUD_PASSWORD=your_app_password \
+  uvx nextcloud-mcp-server run
+```
+
+Or add it directly to your MCP client configuration (e.g. `claude_desktop_config.json` or `.claude/settings.json`):
+
+```json
+{
+  "mcpServers": {
+    "nextcloud": {
+      "command": "uvx",
+      "args": ["nextcloud-mcp-server", "run"],
+      "env": {
+        "NEXTCLOUD_HOST": "https://your.nextcloud.instance.com",
+        "NEXTCLOUD_USERNAME": "your_username",
+        "NEXTCLOUD_PASSWORD": "your_app_password"
+      }
+    }
+  }
+}
+```
+
+> [!TIP]
+> Generate an [app password](https://docs.nextcloud.com/server/latest/user_manual/en/session_management.html#managing-devices) in Nextcloud under **Settings > Security > Devices & sessions** instead of using your login password.
+
+### Docker
 
 For full features including semantic search, run with Docker:
 
@@ -35,9 +67,6 @@ docker run -p 127.0.0.1:8000:8000 --env-file .env --rm \
 curl http://127.0.0.1:8000/health/ready
 
 # 4. Connect to the endpoint
-http://127.0.0.1:8000/sse
-
-# Or with --transport streamable-http
 http://127.0.0.1:8000/mcp
 ```
 
@@ -62,7 +91,7 @@ docker compose --profile login-flow up -d         # Port 8004
 - **Document Processing** - OCR and text extraction from PDFs, DOCX, images with progress notifications
 - **Flexible Deployment** - Docker, Kubernetes ([Helm chart](https://github.com/cbcoutinho/helm-charts)), VM, or local installation
 - **Production-Ready Auth** - Basic Auth with app passwords (recommended) or OAuth2/OIDC (experimental)
-- **Multiple Transports** - SSE, HTTP, and streamable-http support
+- **Multiple Transports** - stdio (default) and streamable-http
 
 ## Supported Apps