docs: add Claude AI assistant rules and configuration

Add comprehensive rule documentation for AI-assisted development covering
authentication surfaces, outbound-call safety invariants, and other project
conventions to guide Claude's understanding of critical system behaviors.

docs/mcp-server.md

@@ -3,8 +3,11 @@
 The MCP (Model Context Protocol) server lets any MCP-compatible AI assistant
 control the Hold Slayer gateway. Built with [FastMCP](https://github.com/jlowin/fastmcp),
 it is mounted on the FastAPI app at **`/mcp/`** (trailing slash) over
-**streamable HTTP** and authenticates with the same static bearer token as the
-REST API and WebSocket.
+**streamable HTTP** and authenticates with an owner-minted Personal Access Token
+(`hs_pat_…`) — the same owner-only auth as the REST API and WebSocket. Auth is
+enforced by an ASGI guard (`_owner_only_mcp` in `main.py`) that resolves the
+bearer to the owner; a Casdoor JWT also works, but MCP clients can't refresh one,
+so a PAT is the intended credential.
 
 ## Overview
 
@@ -158,7 +161,7 @@ Claude Code:
 
 ```bash
 claude mcp add hold-slayer --transport http http://localhost:8000/mcp/ \
-  --header "Authorization: Bearer $API_TOKEN"
+  --header "Authorization: Bearer hs_pat_..."
 ```
 
 Generic MCP client configuration:
@@ -168,7 +171,7 @@ Generic MCP client configuration:
   "mcpServers": {
     "hold-slayer": {
       "url": "http://localhost:8000/mcp/",
-      "headers": {"Authorization": "Bearer <API_TOKEN>"}
+      "headers": {"Authorization": "Bearer hs_pat_..."}
     }
   }
 }