deps: add mcp[cli] for in-app MCP server

First step of the MCP-first pivot. Adds the official Anthropic MCP SDK
so we can mount a FastMCP HTTP endpoint inside the main Quart app.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -23,6 +23,7 @@ dependencies = [
     "trafilatura>=1.12",
     "APScheduler>=3.10,<4.0",
     "pywebpush>=2.0",
+    "mcp[cli]>=1.0",
 ]
 
 [project.optional-dependencies]