Feature Request: Support for double-tap hotkeys (e.g., Ctrl+Ctrl) #248

Body:

Feature Request

Description

It would be great to add support for double-tap hotkeys (sequential key presses) as an alternative to simultaneous key combinations.

Example use cases:

• Ctrl+Ctrl (double-tap Ctrl)
• Alt+Alt (double-tap Alt)
• Shift+Shift (double-tap Shift)

Why is this useful?

1. Ergonomics — double-tap is easier to press than modifier+key combinations
2. Fewer conflicts — most applications don't use double-tap shortcuts, so less chance of hotkey collision
3. Popular pattern — many tools use this approach (e.g., JetBrains IDEs use double-Shift for "Search Everywhere", IntelliJ uses double-Ctrl for "Run Anything")
4. Accessibility — single-hand operation without stretching fingers

Suggested implementation

The pynput library supports this through event timing. Here's a basic approach:

from pynput import keyboard
import time

class DoubleTapDetector:
    def __init__(self, key, callback, threshold=0.3):
        self.key = key
        self.callback = callback
        self.threshold = threshold  # seconds
        self.last_press = 0
        self.last_release = 0
    
    def on_press(self, key):
        if key == self.key:
            current = time.time()
            # Check if this is a double-tap
            if current - self.last_release < self.threshold:
                self.callback()
            self.last_press = current
    
    def on_release(self, key):
        if key == self.key:
            self.last_release = time.time()

Alternative libraries

If pynput proves limiting, consider:

The keyboard library might be the easiest path — it already supports sequences and double-tap patterns natively:

import keyboard

# Double-tap Ctrl
keyboard.add_hotkey('ctrl+ctrl', invoke_writing_tools)

# Or with custom timing
keyboard.add_hotkey('ctrl, ctrl', invoke_writing_tools, timeout=0.3)

Configuration suggestion

Allow users to specify hotkey type in config:

{
  "hotkey": "ctrl+ctrl",
  "hotkey_type": "double-tap"  // or "simultaneous"
}

Environment

• OS: Linux (X11/Wayland), Windows
• Writing Tools version: v8

Thank you for this amazing tool! 🙏