Add filesystem scan trigger and version badge features

Implements optional filesystem scan triggering for Plex and Audiobookshelf after file organization, with new settings in the admin UI, setup wizard, and API. Updates documentation to reflect scan trigger options and improved file organization/cleanup logic. Refactors dropdown menus to use smart positioning and portals for better UX. Adds a version API route and a VersionBadge component to display build info in the header. Updates Docker build to inject version metadata.

documentation/phase3/file-organization.md

@@ -37,7 +37,46 @@ Default: `/media/audiobooks/` (if not configured)
 5. **Copy** files (not move - originals stay for seeding)
 6. **Tag metadata** (if enabled) - writes correct title, author, narrator, ASIN to audio files
 7. Copy cover art if found, else download from Audible
-8. Originals remain until seeding requirements met
+8. Update request status to `downloaded`
+9. **Trigger filesystem scan** (if enabled) - tells Plex/ABS to scan for new files
+10. Originals remain until seeding requirements met
+
+## Filesystem Scan Triggering
+
+**Status:** ✅ Implemented (Both Backends)
+
+**Purpose:** Trigger Plex/Audiobookshelf to scan filesystem after organizing files, ensuring new books appear immediately for users with disabled filesystem watchers.
+
+**Configuration:**
+- Plex: `plex.trigger_scan_after_import` (boolean, default: false)
+- Audiobookshelf: `audiobookshelf.trigger_scan_after_import` (boolean, default: false)
+
+**Flow:**
+1. Files organized to media directory
+2. Request status updated to `downloaded`
+3. Check config setting (backend-specific)
+4. If enabled: Call `ILibraryService.triggerLibraryScan(libraryId)`
+5. Media server scans filesystem (async operation)
+6. RMAB's scheduled check eventually detects new book
+7. Request status updates to `available`
+
+**Implementation:**
+- Uses existing `ILibraryService` abstraction
+- `PlexLibraryService.triggerLibraryScan()` → `POST /library/sections/{id}/refresh`
+- `AudiobookshelfLibraryService.triggerLibraryScan()` → `POST /api/libraries/{id}/scan`
+- Called from `organize-files.processor.ts` after status update
+- Backend-agnostic using factory pattern
+
+**Error Handling:**
+- Scan failures logged but don't fail organize job
+- Graceful degradation: scheduled scans eventually detect the book
+- Non-blocking: async operation doesn't delay other jobs
+
+**Use Cases:**
+- Users with Plex/ABS filesystem watcher disabled
+- Network-mounted media directories with delayed inotify
+- Users who prefer manual control over automatic scanning
+- Most users keep this disabled (default) and rely on built-in watchers
 
 ## Metadata Tagging
 
@@ -107,10 +146,21 @@ exiftool "audiobook.m4b" | grep -i asin
 **Config:** `seeding_time_minutes` (0 = unlimited, never cleanup)
 
 **Cleanup Job:** `cleanup_seeded_torrents` (every 30 mins)
-1. Check 'available' and 'downloaded' status requests with download history
+1. Find requests with status 'available' or soft-deleted (orphaned downloads)
 2. Query qBittorrent for actual `seeding_time` field
-3. Delete torrent + files only after requirement met
-4. Respects config (0 = never cleanup)
+3. **CRITICAL: Check if torrent hash is shared by other active requests**
+   - If yes → Skip torrent deletion, only hard-delete the soft-deleted request record
+   - If no → Delete torrent + files
+4. Delete torrent + files only after seeding requirement met
+5. Respects config (0 = never cleanup)
+
+**Shared Torrent Protection:**
+When user deletes and re-requests the same audiobook:
+- Both requests share the same torrent hash (same files)
+- Cleanup finds old soft-deleted request
+- Before deleting torrent, checks if any active (non-deleted) request uses same hash
+- If found → Keeps torrent, only removes soft-deleted database record
+- Prevents deleting source files for active requests during chapter merging
 
 ## Interface