fix: delete thumbnails when files are permanently deleted

- Inject ThumbnailService into TrashService and FileManagementService
- Call delete_thumbnails() after permanent file deletion in:
  - TrashService::delete_permanently (single item)
  - TrashService::empty_trash (bulk: collects file IDs first)
  - FileManagementService::delete_file
  - FileManagementService::delete_with_cleanup (fallback path)
- All thumbnail cleanup is best-effort (warn on failure, never blocks)
- Prevents orphaned thumbnail files from accumulating on disk

src/application/services/file_management_service.rs

@@ -8,6 +8,7 @@ use crate::application::services::trash_service::TrashService;
 use crate::common::errors::DomainError;
 use crate::infrastructure::repositories::pg::file_blob_read_repository::FileBlobReadRepository;
 use crate::infrastructure::repositories::pg::file_blob_write_repository::FileBlobWriteRepository;
+use crate::infrastructure::services::thumbnail_service::ThumbnailService;
 use tracing::{error, info, warn};
 use uuid::Uuid;
 
@@ -21,6 +22,7 @@ pub struct FileManagementService {
     file_repository: Arc<FileBlobWriteRepository>,
     file_read: Option<Arc<FileBlobReadRepository>>,
     trash_service: Option<Arc<TrashService>>,
+    thumbnail_service: Option<Arc<ThumbnailService>>,
 }
 
 impl FileManagementService {
@@ -30,6 +32,7 @@ impl FileManagementService {
             file_repository,
             file_read: None,
             trash_service: None,
+            thumbnail_service: None,
         }
     }
 
@@ -38,11 +41,13 @@ impl FileManagementService {
         file_repository: Arc<FileBlobWriteRepository>,
         trash_service: Option<Arc<TrashService>>,
         file_read: Option<Arc<FileBlobReadRepository>>,
+        thumbnail_service: Option<Arc<ThumbnailService>>,
     ) -> Self {
         Self {
             file_repository,
             file_read,
             trash_service,
+            thumbnail_service,
         }
     }
 
@@ -171,7 +176,14 @@ impl FileManagementUseCase for FileManagementService {
     }
 
     async fn delete_file(&self, id: &str) -> Result<(), DomainError> {
-        self.file_repository.delete_file(id).await
+        self.file_repository.delete_file(id).await?;
+        // Best-effort thumbnail cleanup
+        if let Some(thumb) = &self.thumbnail_service {
+            if let Err(e) = thumb.delete_thumbnails(id).await {
+                warn!("Failed to delete thumbnails for file {}: {}", id, e);
+            }
+        }
+        Ok(())
     }
 
     async fn delete_file_owned(&self, id: &str, caller_id: Uuid) -> Result<(), DomainError> {
@@ -210,6 +222,12 @@ impl FileManagementUseCase for FileManagementService {
         // Step 2: Permanent delete — trigger handles blob ref_count
         warn!("Permanently deleting file: {}", id);
         self.file_repository.delete_file(id).await?;
+        // Best-effort thumbnail cleanup
+        if let Some(thumb) = &self.thumbnail_service {
+            if let Err(e) = thumb.delete_thumbnails(id).await {
+                warn!("Failed to delete thumbnails for file {}: {}", id, e);
+            }
+        }
         info!("File permanently deleted: {}", id);
 
         Ok(false) // permanently deleted

src/application/services/trash_service.rs

@@ -1,5 +1,5 @@
 use std::sync::Arc;
-use tracing::{debug, error, info, instrument};
+use tracing::{debug, error, info, instrument, warn};
 use uuid::Uuid;
 
 use crate::application::dtos::trash_dto::TrashedItemDto;
@@ -13,6 +13,7 @@ use crate::infrastructure::repositories::pg::file_blob_read_repository::FileBlob
 use crate::infrastructure::repositories::pg::file_blob_write_repository::FileBlobWriteRepository;
 use crate::infrastructure::repositories::pg::folder_db_repository::FolderDbRepository;
 use crate::infrastructure::repositories::pg::trash_db_repository::TrashDbRepository;
+use crate::infrastructure::services::thumbnail_service::ThumbnailService;
 
 /**
  * Application service for trash operations.
@@ -40,6 +41,9 @@ pub struct TrashService {
     /// Port for folder operations (get folder, trash, restore, delete)
     folder_storage_port: Arc<FolderDbRepository>,
 
+    /// Thumbnail service for cleaning up thumbnails on permanent delete
+    thumbnail_service: Option<Arc<ThumbnailService>>,
+
     /// Number of days items should be kept in trash before automatic cleanup
     retention_days: u32,
 }
@@ -51,12 +55,14 @@ impl TrashService {
         file_write_port: Arc<FileBlobWriteRepository>,
         folder_storage_port: Arc<FolderDbRepository>,
         retention_days: u32,
+        thumbnail_service: Option<Arc<ThumbnailService>>,
     ) -> Self {
         Self {
             trash_repository,
             file_read_port,
             file_write_port,
             folder_storage_port,
+            thumbnail_service,
             retention_days,
         }
     }
@@ -557,6 +563,14 @@ impl TrashUseCase for TrashService {
                                 }
                             }
                         }
+
+                        // Best-effort thumbnail cleanup — thumbnails are cache
+                        // artifacts, so failure must not block file deletion.
+                        if let Some(thumb) = &self.thumbnail_service {
+                            if let Err(e) = thumb.delete_thumbnails(&file_id).await {
+                                warn!("Failed to delete thumbnails for file {}: {}", file_id, e);
+                            }
+                        }
                     }
                     TrashedItemType::Folder => {
                         // Permanently delete the folder
@@ -647,6 +661,25 @@ impl TrashUseCase for TrashService {
     async fn empty_trash(&self, user_id: Uuid) -> Result<()> {
         info!("Emptying trash for user {}", user_id);
 
+        // Collect trashed file IDs BEFORE bulk-deleting so we can clean up
+        // their thumbnails afterward.  This is best-effort — if the query
+        // fails we still proceed with the bulk delete.
+        let trashed_file_ids: Vec<String> = if self.thumbnail_service.is_some() {
+            match self.trash_repository.get_trash_items(&user_id).await {
+                Ok(items) => items
+                    .iter()
+                    .filter(|i| matches!(i.item_type(), TrashedItemType::File))
+                    .map(|i| i.original_id().to_string())
+                    .collect(),
+                Err(e) => {
+                    warn!("Could not list trashed items for thumbnail cleanup: {}", e);
+                    Vec::new()
+                }
+            }
+        } else {
+            Vec::new()
+        };
+
         // clear_trash() already performs bulk SQL DELETEs in 2 queries:
         //   1. DELETE FROM storage.files  WHERE user_id = $1 AND is_trashed = TRUE
         //   2. DELETE FROM storage.folders WHERE user_id = $1 AND is_trashed = TRUE
@@ -659,6 +692,15 @@ impl TrashUseCase for TrashService {
         // Finally it clears the trash_items index for the user.
         self.trash_repository.clear_trash(&user_id).await?;
 
+        // Best-effort thumbnail cleanup for all deleted files
+        if let Some(thumb) = &self.thumbnail_service {
+            for file_id in &trashed_file_ids {
+                if let Err(e) = thumb.delete_thumbnails(file_id).await {
+                    warn!("Failed to delete thumbnails for file {}: {}", file_id, e);
+                }
+            }
+        }
+
         info!("Trash emptied for user {}", user_id);
         Ok(())
     }

src/common/di.rs

@@ -261,6 +261,7 @@ impl AppServiceFactory {
             repos.file_write_repository.clone(),
             trash_service.clone(),
             Some(repos.file_read_repository.clone()),
+            Some(core.thumbnail_service.clone()),
         ));
 
         let file_use_case_factory = Arc::new(AppFileUseCaseFactory::new(
@@ -302,6 +303,7 @@ impl AppServiceFactory {
     pub async fn create_trash_service(
         &self,
         repos: &RepositoryServices,
+        core: &CoreServices,
     ) -> Option<Arc<TrashService>> {
         if !self.config.features.enable_trash {
             tracing::info!("Trash service is disabled in configuration");
@@ -317,6 +319,7 @@ impl AppServiceFactory {
             repos.file_write_repository.clone(),
             repos.folder_repository.clone(),
             self.config.storage.trash_retention_days,
+            Some(core.thumbnail_service.clone()),
         ));
 
         // Initialize cleanup service (bulk-deletes expired items in 2 SQL queries)
@@ -457,7 +460,7 @@ impl AppServiceFactory {
         let repos = self.create_repository_services(&core, &pool);
 
         // 3. Trash service (needed before application services)
-        let trash_service = self.create_trash_service(&repos).await;
+        let trash_service = self.create_trash_service(&repos, &core).await;
 
         // 4. Application services (with trash already wired)
         let mut apps = self.create_application_services(&core, &repos, trash_service.clone());