[Thino] Add keyboard shortcut (cmd+Enter) for Save button

[inadysensei]

Current Behavior

• Currently, the Save button in Thino can only be clicked with the mouse
• No keyboard shortcut exists for this action

Requested Feature

• Add keyboard shortcut (Command+Enter on Mac, Ctrl+Enter on Windows/Linux) to trigger the Save button
• This would improve workflow efficiency, especially when creating multiple Thinos

Use Case

• When creating multiple Thinos, having to move the mouse to click the Save button each time interrupts the workflow
• A keyboard shortcut would allow for faster and more efficient note creation

Additional Context

• This is a common shortcut pattern used in many applications for saving/submitting
• Similar to how Obsidian's Quick Add plugin uses Enter to confirm