feat: merge multi-image UX — batch processing, filmstrip navigation, resize/rotate redesign

Integrates feature/multi-image-ux branch with 20 commits including:
- Multi-image viewer with arrow navigation and filmstrip thumbnails
- Batch processing across all tool settings components
- File store rewrite with FileEntry model for multi-image support
- Resize settings redesigned with tab-based UI (presets, custom, scale)
- Side-by-side comparison for resize results
- Per-file metadata caching in strip-metadata
- Client-side ZIP extraction via fflate
- SSE progress correlation via clientJobId

apps/api/src/routes/batch.ts

@@ -42,6 +42,7 @@ export async function registerBatchRoutes(
       // Parse multipart: collect all files and the settings field
       const files: ParsedFile[] = [];
       let settingsRaw: string | null = null;
+      let clientJobId: string | null = null;
 
       try {
         const parts = request.parts();
@@ -60,6 +61,8 @@ export async function registerBatchRoutes(
             }
           } else if (part.fieldname === "settings") {
             settingsRaw = part.value as string;
+          } else if (part.fieldname === "clientJobId") {
+            clientJobId = part.value as string;
           }
         }
       } catch (err) {
@@ -102,7 +105,7 @@ export async function registerBatchRoutes(
       }
 
       // Create a job ID for progress tracking
-      const jobId = randomUUID();
+      const jobId = clientJobId || randomUUID();
 
       const progress: JobProgress = {
         jobId,
@@ -120,6 +123,7 @@ export async function registerBatchRoutes(
         "Content-Disposition": `attachment; filename="batch-${toolId}-${jobId.slice(0, 8)}.zip"`,
         "Transfer-Encoding": "chunked",
         "X-Job-Id": jobId,
+        "X-File-Order": files.map(f => f.filename).join(","),
       });
 
       // Create ZIP archive that pipes directly to the response