fix(cli): remove quote-based drag detection to prevent input lag

[euxaristia]

TLDR

Fixes significant input lag when typing single quote (') and double quote (") characters by removing the quote-based drag-and-drop detection mechanism. The previous implementation delayed broadcasting quote characters by 100ms, causing noticeable lag during normal typing. Modern terminals use bracketed paste mode for file drag-and-drop, making the quote-based heuristic unnecessary.

Dive Deeper

Root Cause

The KeypressContext had a quote-based drag-and-drop detection mechanism that:

1. Detected when a quote character was typed
2. Buffered the character for 100ms waiting to see if more characters followed (indicating a file path from drag-and-drop)
3. Only then broadcast the character

This caused a 100ms delay on every quote keystroke, which is very noticeable during typing.

The Fix

Removed the quote-based drag detection entirely because:

• Modern terminals use bracketed paste mode (PASTE_MODE_PREFIX = ESC[200~) for file drag-and-drop operations
• The bracketed paste handling is already implemented and working correctly
• The quote-based heuristic was a fallback for legacy terminals that compromised the typing experience for all users

Changes

• Removed quote character special handling (SINGLE_QUOTE, DOUBLE_QUOTE detection)
• Removed unused drag-related refs and timers (isDraggingRef, dragBufferRef, draggingTimerRef)
• Removed drag cleanup code on exit
• Updated tests to reflect new behavior (quotes broadcast immediately)
• Total: ~75 lines of code removed

Impact

✅ Eliminates input lag when typing quotes and all other characters
✅ Maintains drag-and-drop support via bracketed paste mode (modern terminals)
✅ Cleaner, simpler code with less complexity
⚠️ Legacy terminals that don't support bracketed paste for file drops may need to use Ctrl+V for pasting file paths (this is already supported)

Reviewer Test Plan

1. Pull and run the code: bun install && bun start
2. Type messages containing single and double quotes:
   • It's working!
   • echo "hello world"
   • const x = 'test';
3. Verify quotes appear immediately without any lag
4. Test file drag-and-drop (if your terminal supports it):
   • Drag a file into the terminal window
   • The file path should still appear correctly via bracketed paste mode
5. Run tests: bun test

Testing Matrix

	🍏 macOS	🪟 Windows	🐧 Linux
npm run	❓	❓	✅
npx	❓	❓	❓
Docker	❓	❓	❓
Podman	❓	-	❓

Tested on Linux with bun - quotes now appear instantly with no lag.

Linked issues / bug

Fixes input lag when typing quote characters (no existing issue filed)