feat: Diagnostic Report Enhancements

[malec-palec]

Features

• Press F7 to open diagnostic report at any time
• Scans project for missing actions/conditions/expressions from extensions
• Scans project for invalid parameters (shown with red underline in Events Sheet)
• Click on error location to navigate directly to the event
• Event is highlighted for 3 seconds after navigation (like search results)
• Works for both scene events and external events

UI Improvements

• Two-column layout: Location + Instruction
• Action/Condition shown in bold at the beginning
• Long text truncated with "..."
• Click on text or arrow button to expand/collapse
• Arrow button only appears when text is truncated

Preferences

• New option: "Block preview and export when diagnostic errors are found"
• Disabled by default
• Shows alert with error count and F7 hint when blocking

Tests & Documentation

• Unit tests for validation scanner
• Storybook stories for dialog
• New documentation page