feat: add adaptive shortcut recording and management

[devmobasa]

Summary

Overhauls Wayscriber’s keybinding experience while preserving the existing text-based configuration format.

• Adds click-to-record keyboard shortcuts with an Edit as Text fallback.
• Supports Super/Meta bindings.
• Supports auxiliary mouse buttons and stylus barrel buttons.
• Adds bounded multi-step sequences such as Ctrl+K > Ctrl+C.
• Adds a bulk shortcut manager with search, filtering, conflict review, source badges, availability indicators, and reset controls.
• Displays shortcuts as distinct keycaps with separate removal buttons.

Runtime behavior

• Dispatches recorded keyboard and device shortcuts consistently across the canvas, built-in toolbar, and GTK toolbar.
• Prevents auxiliary-button actions from firing behind active modals.
• Handles sequence prefixes, timeouts, shifted punctuation, and key auto-repeat safely.
• Aligns keypad, non-ASCII, mouse-button, and stylus translation between the configurator and runtime.
• Preserves compatibility with existing text-authored shortcuts and feature-gated builds.

Configuration safety

• Keeps edits draft-only until Save.
• Detects exact, cross-action, and prefix conflicts.
• Resolves conflicts without discarding unrelated sequence branches or falling back to the complete default keymap.
• Preserves whether bindings were explicitly authored, including values equal to defaults.
• Restores clean/default state when an originally omitted binding is edited and then reverted.
• Keeps invalid text visible and reports field-level validation errors without writing the configuration.