fix: dispose LSP children on MCP stdio close (#47)

[Fortune0001]

Fixes #47.

Summary

Adds process.stdin close and end handlers in index.ts that mirror the existing SIGTERM handler. Without these, when the parent MCP client (e.g. claude -p) exits and closes the stdio transport, cclsp keeps running and its spawned LSP children (pylsp, typescript-language-server) become orphaned. On Windows this accumulates to OOM-class memory pressure across long-running parent sessions.

Change

 process.on('SIGTERM', () => {
   lspClient.dispose();
   process.exit(0);
 });

+process.stdin.on('close', () => {
+  lspClient.dispose();
+  process.exit(0);
+});
+
+process.stdin.on('end', () => {
+  lspClient.dispose();
+  process.exit(0);
+});

lspClient.dispose() already cleans up LSP children correctly (delegates to ServerManager.dispose() in src/lsp/). The only missing piece was invoking it on the stdio-close path.

Test plan

• bun test — 218 pass, 9 skip, 0 fail
• Manual smoke: with the patched build, fire many claude -p calls in a loop in a Python-heavy workspace, then enumerate orphan python.exe processes whose command line contains pylsp — should be 0 (was ~100 before the patch).

Happy to iterate if you'd prefer a different shape (e.g., transport.onclose instead of process.stdin.on('close')) — both achieve the same thing and I went with the process.stdin form to mirror the surrounding signal handlers. Let me know.