Feature request: make overlay summon shortcuts configurable

[rapidrabbit76]

Description

The summon shortcut is currently hard-coded to Alt+Space with Cmd+Shift+K as a fallback.

That makes the overlay harder to use in real workflows where those combos are already claimed by other launchers, input sources, or OS-level tools. There is already an open issue about overlay conflicts with Raycast (#17), and customizable summon shortcuts would help reduce that friction.

Why this matters

• Alt+Space can conflict with launchers or input-source behavior
• Cmd+Shift+K may already be used by editor or terminal workflows
• some users may want to disable one binding entirely and keep only one shortcut
• the current behavior requires source edits and a rebuild just to change a keybind

Request

Add a small settings flow for the overlay summon shortcut:

1. allow changing the primary shortcut
2. allow changing the secondary shortcut
3. allow clearing either binding entirely
4. persist the values across restarts
5. validate conflicts / invalid accelerators and show an error instead of failing silently

Suggested UX

A minimal settings popover would be enough:

• editable primary shortcut
• editable secondary shortcut
• optional key-recording button
• clear/remove binding action

This does not need a full preferences window. A lightweight settings UI would probably be enough.

Current workaround

Patch the source locally and rebuild the app.

That works, but it is much heavier than it should be for a basic keybinding preference.