feat: Implement graceful server shutdown with signal handling and interval clearing.

docs/development/CENTRAL.md

@@ -33,3 +33,4 @@
 - [Multi-Expansion Selection](./devlog/2025-12-16-230500_multi_expansion_selection.md): Completed. Implemented searchable multi-select interface for "From Expansion" pack generation, allowing mixed-set drafts.
 - [Game Type Filter](./devlog/2025-12-16-231000_game_type_filter.md): Completed. Added Paper/Digital filter to the expansion selection list.
 - [Incremental Caching](./devlog/2025-12-16-233000_incremental_caching.md): Completed. Refactored data fetching to cache cards to the server incrementally per set, preventing PayloadTooLarge errors.
+- [Server Graceful Shutdown Fix](./devlog/2025-12-17-002000_server_shutdown_fix.md): Completed. Implemented signal handling to ensure clean process exit on Ctrl+C.

docs/development/devlog/2025-12-17-002000_server_shutdown_fix.md

@@ -0,0 +1,17 @@
+# Server Graceful Shutdown Fix
+
+## Context
+The user reported that the application process was not exiting clean (hanging for >5s) after pressing Ctrl+C. This indicated active handles (like intervals or open sockets) were preventing the Node.js process from terminating effectively.
+
+## Changes
+Modified `src/server/index.ts` to implement a proper graceful shutdown mechanism:
+1.  **Interval Management**: Captured the global draft timer `setInterval` ID into a variable `draftInterval`.
+2.  **Shutdown Handler**: Created a `gracefulShutdown` function that:
+    - Clears the `draftInterval`.
+    - Closes the Socket.IO server (`io.close()`).
+    - Closes the HTTP server (`httpServer.close()`), waiting for existing connections to close, then exits with code 0.
+    - Sets a 10-second timeout to force exit with code 1 if connections don't close in time.
+3.  **Signal Listeners**: Attached `gracefulShutdown` to `SIGINT` and `SIGTERM` events.
+
+## Impact
+The server should now exit immediately and cleanly when stopped via the terminal, ensuring no zombie processes or port conflicts during development restarts.