feat(settings): add orphaned thumbnail cleanup to General section

Scans the thumbnails directory and cross-references against thumbnail_path
values in the images table, deleting any files not linked to an indexed image.
Surfaces count and reclaimable MB in the General section alongside the
existing Compact database card.

src-tauri/src/commands.rs

@@ -1747,3 +1747,100 @@ pub async fn vacuum_database(app: AppHandle, db: State<'_, DbState>) -> Result<V
         freed_mb: before_bytes.saturating_sub(after_bytes) as f64 / 1_048_576.0,
     })
 }
+
+#[derive(serde::Serialize)]
+pub struct OrphanedThumbnailsInfo {
+    pub count: u64,
+    pub size_mb: f64,
+}
+
+#[derive(serde::Serialize)]
+pub struct CleanupOrphanedThumbnailsResult {
+    pub deleted_count: u64,
+    pub freed_mb: f64,
+}
+
+fn collect_db_thumbnail_filenames(conn: &rusqlite::Connection) -> Result<std::collections::HashSet<String>, String> {
+    let mut stmt = conn
+        .prepare("SELECT thumbnail_path FROM images WHERE thumbnail_path IS NOT NULL")
+        .map_err(|e| e.to_string())?;
+    let set = stmt
+        .query_map([], |row| row.get::<_, String>(0))
+        .map_err(|e| e.to_string())?
+        .filter_map(|r| r.ok())
+        .filter_map(|p| {
+            std::path::Path::new(&p)
+                .file_name()
+                .and_then(|f| f.to_str())
+                .map(|s| s.to_owned())
+        })
+        .collect();
+    Ok(set)
+}
+
+#[tauri::command]
+pub async fn get_orphaned_thumbnails_info(
+    app: AppHandle,
+    db: State<'_, DbState>,
+) -> Result<OrphanedThumbnailsInfo, String> {
+    let app_dir = app.path().app_data_dir().map_err(|e| e.to_string())?;
+    let thumb_dir = app_dir.join("thumbnails");
+
+    let conn = db.get().map_err(|e| e.to_string())?;
+    let db_filenames = collect_db_thumbnail_filenames(&conn)?;
+    drop(conn);
+
+    let mut count = 0u64;
+    let mut size_bytes = 0u64;
+
+    if thumb_dir.exists() {
+        for entry in std::fs::read_dir(&thumb_dir).map_err(|e| e.to_string())? {
+            let entry = entry.map_err(|e| e.to_string())?;
+            let fname = entry.file_name();
+            if !db_filenames.contains(fname.to_string_lossy().as_ref()) {
+                size_bytes += entry.metadata().map(|m| m.len()).unwrap_or(0);
+                count += 1;
+            }
+        }
+    }
+
+    Ok(OrphanedThumbnailsInfo {
+        count,
+        size_mb: size_bytes as f64 / 1_048_576.0,
+    })
+}
+
+#[tauri::command]
+pub async fn cleanup_orphaned_thumbnails(
+    app: AppHandle,
+    db: State<'_, DbState>,
+) -> Result<CleanupOrphanedThumbnailsResult, String> {
+    let app_dir = app.path().app_data_dir().map_err(|e| e.to_string())?;
+    let thumb_dir = app_dir.join("thumbnails");
+
+    let conn = db.get().map_err(|e| e.to_string())?;
+    let db_filenames = collect_db_thumbnail_filenames(&conn)?;
+    drop(conn);
+
+    let mut deleted_count = 0u64;
+    let mut freed_bytes = 0u64;
+
+    if thumb_dir.exists() {
+        for entry in std::fs::read_dir(&thumb_dir).map_err(|e| e.to_string())? {
+            let entry = entry.map_err(|e| e.to_string())?;
+            let fname = entry.file_name();
+            if !db_filenames.contains(fname.to_string_lossy().as_ref()) {
+                let size = entry.metadata().map(|m| m.len()).unwrap_or(0);
+                if std::fs::remove_file(entry.path()).is_ok() {
+                    deleted_count += 1;
+                    freed_bytes += size;
+                }
+            }
+        }
+    }
+
+    Ok(CleanupOrphanedThumbnailsResult {
+        deleted_count,
+        freed_mb: freed_bytes as f64 / 1_048_576.0,
+    })
+}

src-tauri/src/lib.rs

@@ -146,6 +146,8 @@ pub fn run() {
             commands::open_app_data_folder,
             commands::get_database_info,
             commands::vacuum_database,
+            commands::get_orphaned_thumbnails_info,
+            commands::cleanup_orphaned_thumbnails,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");