Phase 3b: FastMCP "ai service" for claude.ai cooking mode

A standalone MCP server (no Django import) exposing 7 tools over
Streamable HTTP, backed by the Django REST API via the caine token.

- mcp_server/: client.py (httpx wrapper over /api/), server.py (the
  tools + FastMCP app + main), __main__.py, tests.py.
- Tools: get_pantry, set_item_state, add_to_pantry, what_can_i_cook,
  get_recipes, log_cook (suggests, never mutates), create_meta_recipe
  (brainstorm -> commit). Each description says when to call it.
- deploy/food-mcp.service: systemd unit (own process, runs .venv python
  -m mcp_server, loads /var/lib/food/.env).
- deploy/food.tomflux.xyz.nginx: current config + an authless
  /mcp/<secret>/ location proxying to 127.0.0.1:8765 (the URL secret is
  the credential; SSE-friendly buffering/timeout).
- pyproject: [dependency-groups] mcp = [fastmcp, httpx]; deploy with
  `uv sync --group mcp`.

Verified: 7 tools register on fastmcp 3.x, run() accepts transport/
host/port/path, 6 FoodClient unit tests pass (httpx MockTransport).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

mcp_server/tests.py

@@ -0,0 +1,85 @@
+"""Tests for the FoodClient HTTP layer, using httpx.MockTransport (no network,
+no Django, no fastmcp). Run with: python -m unittest mcp_server.tests
+"""
+import json
+import unittest
+
+import httpx
+
+from mcp_server.client import FoodClient, FoodApiError
+
+
+def make_client(handler):
+    transport = httpx.MockTransport(handler)
+    http = httpx.Client(
+        transport=transport,
+        base_url="http://api.test/api",
+        headers={"Authorization": "Token x"},
+    )
+    return FoodClient(http=http)
+
+
+class FoodClientTests(unittest.TestCase):
+    def test_set_state_posts_expected_body(self):
+        captured = {}
+
+        def handler(request):
+            captured["path"] = request.url.path
+            captured["body"] = json.loads(request.content)
+            return httpx.Response(200, json={"state": "out"})
+
+        out = make_client(handler).set_state("noodles", "out", location="cupboard")
+        self.assertEqual(captured["path"], "/api/pantry/set-state/")
+        self.assertEqual(
+            captured["body"],
+            {"ingredient": "noodles", "state": "out", "location": "cupboard"},
+        )
+        self.assertEqual(out["state"], "out")
+
+    def test_set_state_omits_location_when_absent(self):
+        captured = {}
+
+        def handler(request):
+            captured["body"] = json.loads(request.content)
+            return httpx.Response(200, json={})
+
+        make_client(handler).set_state("eggs", "in")
+        self.assertNotIn("location", captured["body"])
+
+    def test_bulk_add_wraps_items(self):
+        captured = {}
+
+        def handler(request):
+            captured["body"] = json.loads(request.content)
+            return httpx.Response(201, json={"added": 1})
+
+        make_client(handler).bulk_add([{"ingredient_name": "eggs"}])
+        self.assertEqual(captured["body"], {"items": [{"ingredient_name": "eggs"}]})
+
+    def test_what_can_i_cook_passes_servings(self):
+        captured = {}
+
+        def handler(request):
+            captured["servings"] = request.url.params.get("servings")
+            return httpx.Response(200, json={"results": []})
+
+        make_client(handler).what_can_i_cook(servings=4)
+        self.assertEqual(captured["servings"], "4")
+
+    def test_error_response_raises(self):
+        def handler(request):
+            return httpx.Response(404, json={"error": "nope"})
+
+        with self.assertRaises(FoodApiError):
+            make_client(handler).set_state("x", "out")
+
+    def test_unreachable_api_raises(self):
+        def handler(request):
+            raise httpx.ConnectError("boom")
+
+        with self.assertRaises(FoodApiError):
+            make_client(handler).pantry()
+
+
+if __name__ == "__main__":
+    unittest.main()