fix: Ctrl+V paste not working in Firefox (SIMPL-39)

[Copilot]

In recent Firefox versions, Monaco never registers editor.action.clipboardPasteAction because its clipboard-support detection explicitly excludes Firefox (navigator.clipboard && !isFirefox) and document.queryCommandSupported('paste') now returns false (deprecated). The existing Ctrl+V keybinding silently fails with "command not found".

Changes

• lib/note-content-editor.tsx — editorReady: After addKeybindingRules, check whether editor.action.clipboardPasteAction was registered. If not, register a fallback under the same ID using navigator.clipboard.readText() + editor.executeEdits():

if (!window.electron && !editor.getAction('editor.action.clipboardPasteAction')) {
  editor.addAction({
    id: 'editor.action.clipboardPasteAction',
    label: 'Paste',
    contextMenuGroupId: '9_cutcopypaste',
    contextMenuOrder: 2,
    run: () => {
      navigator.clipboard.readText().then((text) => {
        const selection = editor.getSelection();
        if (selection) {
          editor.executeEdits('paste', [
            { range: selection, text, forceMoveMarkers: true },
          ]);
        }
      }).catch(() => {
        // clipboard read failed (e.g., permission denied); nothing to paste
      });
    },
  });
}

Using the same action ID means the existing keybinding rule picks up the fallback transparently. The !window.electron + absence-of-action guard ensures Chrome, Safari, and Electron are unaffected.

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[thabotswana]

@mdawaffe can I bug you for a review of this?