matrix: hive-matrix-mcp crate (daemon+stdio bridge) + harness wiring (#548 phase 3)

CLAUDE.md

@@ -203,6 +203,23 @@ hive-forge/        Forgejo CLI wrapper (`hive-forge` binary)
                          attach-comment, lint). Replaces the 600-line
                          hive-forge-tools.nix bash script (closes #280).
 
+hive-matrix-mcp/   per-agent matrix-sdk integration (#548 phase 3).
+  src/main.rs           `hive-matrix-daemon` binary entry — long-running
+                         matrix-sdk Client + sync per agent; serves the
+                         MCP bridge over /run/hive-matrix.sock; emits
+                         hyperhive wake on incoming room events.
+  src/bin/mcp.rs        `hive-matrix-mcp` stdio bridge claude spawns per
+                         turn — connects to the daemon socket, forwards
+                         each tool call (send_message, send_dm,
+                         send_reaction, send_reply, mark_read, list_rooms,
+                         list_room_members, read_room). No matrix-sdk dep
+                         at this entrypoint (pure serde + tokio I/O).
+  src/{client,handlers,socket,timeline,wake,protocol,paths}.rs
+                         shared library modules (matrix-sdk session
+                         restore, request dispatch, unix socket server,
+                         event handler → wake bridge, wire types, env
+                         resolution).
+
 hive-sh4re/        wire types (HostRequest/Response, AgentRequest/Response,
                    ManagerRequest/Response, Message, Approval, HelperEvent)