fix: address secondary code review suggestions - add safety comment for release!, document makeModalKeyboardHandler memoization note

Agent-Logs-Url: https://github.com/matt-pharr/physics-data-viewer/sessions/72507e62-4c26-4717-a751-9a80af82cba5

Co-authored-by: matt-pharr <25289941+matt-pharr@users.noreply.github.com>

Author: Copilot

electron/main/ipc-register-kernels.ts

@@ -136,6 +136,8 @@ export function registerKernelIpcHandlers(
    */
   async function acquireMutex(operation: string): Promise<() => void> {
     const previous = startMutex;
+    // `release` is assigned synchronously inside the Promise executor (before
+    // the executor returns), so the definite-assignment assertion is safe.
     let release!: () => void;
     startMutex = new Promise<void>((r) => { release = r; });
     try {

electron/renderer/src/hooks/makeModalKeyboardHandler.ts

@@ -6,6 +6,10 @@
  * `onCancel`. Used by every PDV dialog with a single text input
  * (CreateScriptDialog, CreateNoteDialog, CreateGuiDialog, SaveAsDialog,
  * etc.) to remove the duplicated inline handler.
+ *
+ * Note: The returned function is a new reference on every call. If passing it
+ * as a prop to a memoized child component, wrap the call in `useCallback` at
+ * the call site to avoid unnecessary re-renders.
  */
 
 import type React from 'react';