Pin mcp exactly so Dependabot can classify its updates correctly

requirements.txt

@@ -1,7 +1,15 @@
 # Official MCP Python SDK (pulls in starlette + uvicorn used by server.py).
 # The upper bound is deliberate: 2.x renamed the server class and changed the
 # transport defaults, so a major bump is never a drop-in. Review before widening.
-mcp>=2.1.1,<3
+# Pinned exactly, not as a `>=2.1.1,<3` range. The range expressed the right
+# policy — never cross into 3.x unreviewed — but it broke Dependabot's
+# auto-merge: its PR title reads "from <3,>=2.1.1 to ...", and
+# dependabot/fetch-metadata parses the leading `3` as the previous version, so
+# every mcp bump classified as semver-major and was left for manual review.
+# An exact pin gives fetch-metadata a clean previous/new pair, so patch and
+# minor bumps auto-merge again while a 3.0.0 still classifies as major and
+# stays manual — same protection, correct classification.
+mcp==2.2.0
 # HTTP client used to call the Parcel REST endpoints. `httpx2` is the client the
 # MCP SDK now ships, so using it keeps a single HTTP stack in the image. It
 # verifies TLS against the system trust store (via truststore) rather than a