FerrisPad v0.9.0-rc.3

Added

• Syntax Highlighting: 50+ languages via syntect with oniguruma regex backend. Chunked non-blocking processing for large files (5000+ lines) with sparse checkpoints every 128 lines for fast incremental re-highlighting.
• Drag-to-Reorder Tabs: Drag tabs left or right with a visual blue drop indicator to reorder open documents.
• Session Schema Versioning: Session files now include a version field for future-proof migration support.

Fixed

• Find No Longer Marks Document as Dirty: FLTK fires the modify callback for selection changes; the dirty flag now only sets when text is actually inserted or deleted.
• View Toggle for Highlighting: Toggling syntax highlighting via the View menu no longer persists to settings. Settings is the authority at startup; View menu toggles only affect the current session.
• Allow Closing App While Dialog is Open: The run_dialog helper checks app::should_program_quit() so the app can exit even with a dialog open.
• Memory Leaks in Syntax Highlighting: Reduced highlighting memory from 290MB to 63MB on large files.
• TextBuffer::text() Memory Leaks: Plugged 3.8MB/call leak via buffer_text_no_leak() helper across find, replace, goto, and session operations.
• Native File Dialogs Restored: Fixed regression that broke native file chooser on Linux.

Changed

• Architecture Refactoring: Extracted HighlightController (11 methods + 5 fields), UpdateController, buffer_utils module, and FindState from AppState for cleaner separation of concerns.
• Error Handling: Added thiserror-based AppError enum replacing Result<T, String> in session, settings, and updater modules.
• Named Constants: Consolidated LARGE_FILE_THRESHOLD into a single module-level constant.
• Website Updated: Features section now reflects syntax highlighting, tabs, find & replace, dark mode, and in-app updates.