v14.114.0 — Architecture Overhaul, Performance, Dead Code Cleanup

Architecture Overhaul

• Decomposed monolithic god-files into focused modules
• EventLoopCtx — 24 handler methods extracted from main.rs (1,476 → 421 lines, -71%)
• file_mouse.rs — 647-line mouse handler extracted from file_manager.rs (-43%)
• file_actions.rs — keyboard action handlers
• nav_helpers.rs — navigation history module
• clipboard.rs — clipboard utilities with OSC 52 fallback
• refresh.rs — async file refresh loop
• UI split into 14 modules (5,060 → 386 lines, -92%)
• App: 120 flat fields → 13 sub-structs; FileState → 4 sub-structs

Performance

• Fixed unconditional redraw on every 250ms Tick (4 redraws/sec → on-demand)
• Short-circuit path_colors HashMap lookups when empty
• Zero-allocation DIVIDER check

New Features

• Marquee drag selection — transparent border rect, Ctrl+drag toggles, Escape cancels
• Cross-pane drop on empty space — DropTarget::CurrentDir(pane_idx)
• Undo close tab (Ctrl+Shift+T) — max 10 closed tabs restored
• 14 theme presets — Legacy Red (default), Cyberpunk, Ocean Deep, Solarized, Gruvbox, Dracula, Tokyo Night, Nord, Catppuccin, Rose Pine, One Dark, Monokai, Paper, Terminal

Quality

• Tests: 78 → 129 (+65%)
• Zero production unwraps
• Zero TODO/FIXME/HACK markers
• All clippy clean, all doc warnings fixed
• Criterion benchmarks for hot paths
• Dead code cleanup: removed tile_queue, duplicate path_colors, layout.rs, dead parameter chains