feat: add MCP server with HTTP/SSE transport for AI integration

Exposes homelab topology to MCP-compatible AI clients (Claude Code, etc.)
over LAN via HTTP/SSE on port 8001.

- New mcp/ service: FastAPI + mcp SDK, SSE transport
- Auth: X-API-Key for AI clients, X-MCP-Service-Key for backend (Docker-internal)
- Resources: canvas, nodes, edges, scan/pending, scan/runs
- Tools: create/update/delete nodes+edges, trigger scan, approve/hide devices
- Backend deps.py: accepts JWT or MCP service key (no plain-text password)
- 40 tests (auth, resources, tools) across asyncio + trio
- docker-compose.yml: mcp service on port 8001
- README: MCP setup section with Claude Code/Desktop config examples

mcp/tests/test_resources.py

@@ -0,0 +1,47 @@
+import pytest
+from unittest.mock import AsyncMock, patch
+from app.resources import read_resource
+
+
+@pytest.fixture
+def mock_backend():
+    with patch("app.resources.backend") as m:
+        m.get = AsyncMock(return_value={"data": "ok"})
+        yield m
+
+
+@pytest.mark.anyio
+async def test_read_canvas(mock_backend):
+    result = await read_resource("homelable://canvas")
+    mock_backend.get.assert_called_once_with("/api/v1/canvas")
+    assert len(result) == 1
+
+
+@pytest.mark.anyio
+async def test_read_nodes(mock_backend):
+    await read_resource("homelable://nodes")
+    mock_backend.get.assert_called_once_with("/api/v1/nodes")
+
+
+@pytest.mark.anyio
+async def test_read_edges(mock_backend):
+    await read_resource("homelable://edges")
+    mock_backend.get.assert_called_once_with("/api/v1/edges")
+
+
+@pytest.mark.anyio
+async def test_read_single_node(mock_backend):
+    await read_resource("homelable://nodes/abc123")
+    mock_backend.get.assert_called_once_with("/api/v1/nodes/abc123")
+
+
+@pytest.mark.anyio
+async def test_read_scan_pending(mock_backend):
+    await read_resource("homelable://scan/pending")
+    mock_backend.get.assert_called_once_with("/api/v1/scan/pending")
+
+
+@pytest.mark.anyio
+async def test_read_unknown_uri(mock_backend):
+    with pytest.raises(ValueError, match="Unknown resource URI"):
+        await read_resource("homelable://unknown")