Fix Cmd+E incorrectly triggering Extract Thought (requires Cmd+Ctrl+E)

[Copilot]

extractThought is bound to { key: 'e', control: true, meta: true } (Cmd+Ctrl+E), but Cmd+E alone was triggering it. Two bugs in src/commands.ts:

• hashCommand silently dropped the control modifier — { key: 'e', control: true, meta: true } encoded as META_E instead of META_CTRL_E
• hashKeyDown had no path to emit CTRL_ — Cmd+E and Cmd+Ctrl+E both produced META_E, colliding with the above

Fix:

// hashCommand: include control in the encoded key
(key.meta ? 'META_' : '') +
(key.control ? 'CTRL_' : '') +   // was missing entirely
...

// hashKeyDown: emit CTRL_ only when both Meta+Ctrl held on Mac
(e.metaKey || e.ctrlKey ? 'META_' : '') +
(isMac && e.ctrlKey && e.metaKey ? 'CTRL_' : '') +  // new
...

isMac && e.ctrlKey && e.metaKey is intentional: on Windows e.ctrlKey already maps to META_, so CTRL_ is a Mac-only concept. Requiring both keys prevents Ctrl-alone on Mac from matching Cmd+Ctrl commands.