fix(mcp): restore HTTP /mcp endpoint after 855 regression

855 deleted the HTTP /mcp route and pointed agents at ws://...crdt-sync,
but Claude Code's .mcp.json doesn't speak ws:// and the rendezvous WS
never had MCP method handlers wired up — so every spawned Claude Code
agent (gateway-routed and local) booted with zero huskies tools and
died on --permission-prompt-tool=mcp__huskies__prompt_permission.

Restore mcp_post_handler / mcp_get_handler / handle_initialize, re-add
the /mcp route, and revert all three .mcp.json writers to emit
http://localhost:{port}/mcp with explicit "type": "http". Reuses the
already-extracted gateway::jsonrpc types and the surviving
dispatch_tool_call / list_tools surfaces — net add ~140 lines.

Federation work is unaffected: /crdt-sync continues to do CRDT sync,
which is what it was actually doing. MCP-over-WebSocket for cross-LAN
agents was never wired up by 855 and can be done as a proper follow-up
with a regression test that boots a real claude and verifies tool
registration.

Verified end-to-end: /mcp initialize, tools/list (74 tools incl.
prompt_permission), and tools/call all respond correctly from inside
the rebuilt container.

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

server/src/io/fs/project.rs

@@ -40,7 +40,7 @@ pub(crate) async fn ensure_project_root_with_story_kit(
         // Always update .mcp.json with the current port so the bot connects to
         // the right endpoint even when HUSKIES_PORT changes between restarts.
         let mcp_content = format!(
-            "{{\n  \"mcpServers\": {{\n    \"huskies\": {{\n      \"url\": \"ws://localhost:{port}/crdt-sync\"\n    }}\n  }}\n}}\n"
+            "{{\n  \"mcpServers\": {{\n    \"huskies\": {{\n      \"type\": \"http\",\n      \"url\": \"http://localhost:{port}/mcp\"\n    }}\n  }}\n}}\n"
         );
         fs::write(path.join(".mcp.json"), mcp_content)
             .map_err(|e| format!("Failed to write .mcp.json: {}", e))?;

server/src/io/fs/scaffold/mod.rs

@@ -69,11 +69,11 @@ pub(crate) fn scaffold_story_kit(root: &Path, port: u16) -> Result<(), String> {
     )?;
 
     // Write .mcp.json at the project root so agents can find the MCP server
-    // via the rendezvous WebSocket endpoint.
+    // via the HTTP MCP endpoint.
     // Only written when missing — never overwrites an existing file, because
     // the port is environment-specific and must not clobber a running instance.
     let mcp_content = format!(
-        "{{\n  \"mcpServers\": {{\n    \"huskies\": {{\n      \"url\": \"ws://localhost:{port}/crdt-sync\"\n    }}\n  }}\n}}\n"
+        "{{\n  \"mcpServers\": {{\n    \"huskies\": {{\n      \"type\": \"http\",\n      \"url\": \"http://localhost:{port}/mcp\"\n    }}\n  }}\n}}\n"
     );
     write_file_if_missing(&root.join(".mcp.json"), &mcp_content)?;