fix(ui): Add mouse interaction toggle to restore native text selection

[JuanCS-Dev]

Fixes #13057 #13074

🐛 The Problem

v0.15.0 broke native terminal text selection and copy/paste for 17+ users by unconditionally enabling mouse event capture when alternate buffer mode is active.

User Impact:

• Cannot select text with mouse (click+drag does nothing)
• Copy/paste broken (right-click menus don't work)
• Only workaround: Shift+drag (non-standard) or rollback to v0.14.0

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🔍 Root Cause

In gemini.tsx (line 185), mouse events are unconditionally enabled when alternate buffer is true:

const mouseEventsEnabled = useAlternateBuffer;  // <-- Problem!
if (mouseEventsEnabled) {
  enableMouseEvents();  // Captures ALL mouse events
}

When mouse events are enabled, the terminal forwards mouse interactions to the app instead of handling them natively. This breaks standard terminal clipboard workflows.

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✅ The Solution

Add a new setting ui.enableMouseInteraction that decouples mouse support from alternate buffer mode:

New Setting

• Name: enableMouseInteraction
• Default: false (preserves native terminal behavior)
• Location: /settings → UI section
• Requires Restart: Yes

Updated Logic

const mouseEventsEnabled =
  useAlternateBuffer && (settings.merged.ui?.enableMouseInteraction === true);

Now users can:

1. ✅ Use alternate buffer WITHOUT mouse capture (default): Native text selection works
2. ✅ Opt-in to mouse interaction: Explicitly enable for mouse scrolling/clicking

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📊 Benefits

• ✅ Restores native text selection and copy/paste by default
• ✅ Backwards compatible (no breaking changes)
• ✅ Gives users explicit control
• ✅ Fixes both #13057 (12👍) and #13074 (5👍) with one change
• ✅ Zero impact on users without alternate buffer

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🔬 Testing

• ✅ npm run build passes
• ✅ All existing tests pass
• ✅ When enableMouseInteraction = false (default), native selection works
• ✅ When useAlternateBuffer = false, no behavior change

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*Ready to mergeecho BEGIN___COMMAND_OUTPUT_MARKER ; PS1= ; PS2= ; unset HISTFILE ; EC=0 ; echo ___BEGIN___COMMAND_DONE_MARKER___0 ; } 🎉