Application menu (File, Edit, Query, View)

[GordonBeeming]

Description

Application menu bar with standard menus.

Menus

• File: New Query (Ctrl+N), Open File (Ctrl+O), Save (Ctrl+S), Save As, Connect, Disconnect, Exit
• Edit: Undo, Redo, Cut, Copy, Paste, Select All, Find (Ctrl+F), Replace (Ctrl+H)
• Query: Execute (F5), Cancel Execution, Execute Selection (Ctrl+Shift+E)
• View: Object Explorer (Ctrl+B), Results (Ctrl+R), Toggle Theme
• Help: About, GitHub Repository

Acceptance Criteria

• Native-feeling menu bar (Tauri menu API or custom HTML menu)
• All keyboard shortcuts wired up
• Disabled states (e.g., Cancel grayed out when no query running)
• macOS: menu in system menu bar