fix(app): Cmd+C/Ctrl+C copies highlighted text in non-editable chat content (#136)

[jeonghun-jj-lee]

Summary

Cmd+C on selected text in the chat panel (rendered messages, code blocks) silently failed — the clipboard retained its previous content. Right-click → Copy worked because it explicitly calls writeClipboardViaBridge.

Root cause

global-clipboard.ts:186 bailed on non-editable targets:

if (!isEditableTarget(target)) return // non-editables keep native behavior

The assumption ("native behavior works") is false inside a VS Code webview iframe. Electron intercepts Cmd+C at the host level before a copy event fires in the iframe DOM.

Fix

Extend the existing capture-phase keydown handler to bridge Cmd+C/X/A for non-editable targets through writeClipboardViaBridge — the same path the context menu already uses.

Behavior

Shortcut	Non-editable target	Effect
Cmd+C	Selection exists	Copies selection to clipboard via bridge
Cmd+C	No selection	No-op (clipboard unchanged)
Cmd+X	Selection exists	Copies selection (no delete — read-only DOM)
Cmd+A	Any	selectAllChildren(document.body)
Cmd+V/Z/Y	Any	No-op (nothing to paste into or undo)

Structure

onKeyDown:
  [framing/modifier/key guards — unchanged]

  if NOT editable:
    C/X → bridge selection via writeClipboardViaBridge
    A   → selectAllChildren(document.body)
    return (V/Z/Y on non-editables: no-op)

  [existing editable logic — unchanged]

Constraints preserved

• CLIPBOARD_SELF_SELECTOR opt-out unaffected (it is paste-only)
• No second event listener introduced
• writeClipboardViaBridge remains the sole outbound clipboard path
• Extension-host side (chat_bridge.ts clipboard-write handler) needs no changes

Fixes #136