* feat: recursive subfolder filtering + gallery tree navigation + thumbnail sizing - Recursive subfolder filtering: selecting an intermediate folder shows all child images - Gallery tree navigation panel with collapsible folder hierarchy (sticky, resizable) - Thumbnail size controls (S/M/L) for adjustable grid density - Fix path collision when multiple gallery roots share overlapping relative paths - Fix auto-detect mode collapsing nested folders to ambiguous basenames - Security test suite for path traversal edge cases Addresses feedback from #126. Fixes code review items P1/P2 from #135. Co-Authored-By: Kai Bowie <kaigtb@proton.me> * style: fix Black formatting in test_path_security.py * feat(gallery): add folder tree sidebar with hierarchical navigation (#126) - Add collapsible folder tree sidebar to gallery view - Support hierarchical year/month/date folder navigation - Include ancestor path expansion for proper tree structure - Add subfolder filtering to gallery image queries - Update admin subfolder dropdown with ancestor support - Fix trailing whitespace in SQL queries Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Kai <noreply@gtb.ai> Co-authored-by: Kai Bowie <kaigtb@proton.me> Co-authored-by: Kai <kai@tachi-02.localdomain> Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>