Split FAB into separate Join and Start listening buttons

• When a meeting is detected, two buttons now appear: "Join (platform)" and "Start listening"
• Join button opens the meeting URL without starting listening
• Start listening button starts listening without opening a new tab
• Join button hides on narrow screens to keep FAB inside note area

Fix image attachment crashes and improve attachment handling

• Images are now saved as files in session folder instead of base64, preventing app freezes
• Preserve original attachment filenames (Obsidian-style)
• Duplicate filenames automatically get numbered suffixes (e.g., "image 1.png")
• Switch to official TipTap image extension with block-level images

Make content folder migration safer

• Content folder changes now copy data instead of moving it
• Original folder is preserved for safety
• Added confirmation dialog explaining the copy-only behavior

Fix authentication token refresh errors

• Handle refresh_token_already_used errors properly
• Clear invalid sessions to prevent lock timeout warnings
• Remove duplicate deep link handler

Improve feedback modal

• Add optional checkbox to attach redacted application logs
• Logs include last 500 lines with user paths, emails, and IP addresses redacted

Show spinner instead of checkmark while local STT is initializing

• Prevents confusing UI state during model initialization