fix: extend Diagnostic Report to cover extension function events

[malec-palec]

Diagnostic Report previously only scanned layout (scene) events and external events for validation errors. This PR extends the JavaScript validation scanner to also scan events inside extension functions - including top-level (free) functions, behavior functions, and object functions - detecting missing instructions and invalid parameters.

• Store-installed extensions are excluded from the scan
• Disabled (commented out) events and their sub-events are skipped everywhere, not just in extensions
• Report items for extension errors show the extension and function name as location, and clicking them opens the extension editor focused on the relevant function and event
• Tests added for extension function scanning, disabled event skipping, and extension error grouping

[4ian]

Hi @malec-palec! Let me know once this is ready for review.