mcp_server: Unix socket server for external tool access

Exposes memory/journal tools over ~/.consciousness/mcp.sock via
JSON-RPC 2.0 (MCP protocol). External processes (consciousness-mcp,
poc-memory) will connect here instead of accessing the store directly.

Handles: initialize, tools/list, tools/call
Dispatches to the same tool handlers the agent uses internally.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/lib.rs

@@ -68,6 +68,9 @@ pub mod cli;
 // Thalamus — universal notification routing and channel infrastructure
 pub mod thalamus;
 
+// MCP server — exposes memory tools over Unix socket
+pub mod mcp_server;
+
 // Re-export at crate root — capnp codegen emits `crate::daemon_capnp::` paths
 pub use thalamus::daemon_capnp;