perf: non-blocking hash + parallel thumbnail generation

- Replace blocking blake3::hash() with DedupService::hash_file() in
  file_upload_service (create_file, update_file). Uses spawn_blocking +
  mmap_rayon instead of blocking the Tokio async worker.
- Parallelize thumbnail resize+encode with rayon par_iter() for the 3
  sizes (Icon, Preview, Large) inside spawn_blocking.

src/application/services/file_upload_service.rs

@@ -8,6 +8,7 @@ use crate::application::services::storage_usage_service::StorageUsageService;
 use crate::common::errors::DomainError;
 use crate::infrastructure::repositories::pg::FileBlobReadRepository;
 use crate::infrastructure::repositories::pg::FileBlobWriteRepository;
+use crate::infrastructure::services::dedup_service::DedupService;
 use crate::infrastructure::services::file_content_cache::FileContentCache;
 use tracing::{debug, info, warn};
 
@@ -211,7 +212,9 @@ impl FileUploadUseCase for FileUploadService {
         tokio::fs::write(temp.path(), content)
             .await
             .map_err(|e| DomainError::internal_error("FileUpload", format!("write temp: {e}")))?;
-        let hash = blake3::hash(content).to_hex().to_string();
+        let hash = DedupService::hash_file(temp.path())
+            .await
+            .map_err(|e| DomainError::internal_error("FileUpload", format!("hash: {e}")))?;
 
         let file = self
             .file_write
@@ -246,7 +249,9 @@ impl FileUploadUseCase for FileUploadService {
         tokio::fs::write(temp.path(), content)
             .await
             .map_err(|e| DomainError::internal_error("FileUpload", format!("write temp: {e}")))?;
-        let hash = blake3::hash(content).to_hex().to_string();
+        let hash = DedupService::hash_file(temp.path())
+            .await
+            .map_err(|e| DomainError::internal_error("FileUpload", format!("hash: {e}")))?;
 
         self.update_file_streaming(
             path,

src/infrastructure/services/thumbnail_service.rs

@@ -1,6 +1,7 @@
 use bytes::Bytes;
 use image::codecs::jpeg::JpegEncoder;
 use image::imageops::FilterType;
+use rayon::prelude::*;
 /**
  * Thumbnail Generation Service
  *
@@ -534,7 +535,7 @@ impl ThumbnailService {
                 let (orig_w, orig_h) = (img.width(), img.height());
 
                 ThumbnailSize::all()
-                    .iter()
+                    .par_iter()
                     .map(|&size| {
                         let max_dim = size.max_dimension();