feat: directory scanner plugin — walk library paths, auto-register assets

- DirectoryScannerPlugin: recursive directory walk via FileStoragePort
- Computes SHA256 checksums, classifies media by extension
- Registers each file via RegisterAssetHandler (triggers AssetIngested → extract_metadata pipeline)
- Reads library_path_id from job payload, looks up volume + path
- Seeded plugin + scan_directory pipeline
- Trigger via POST /jobs with { job_type: "ScanDirectory", payload: { library_path_id: "..." } }

k-photos-frontend/README.md

@@ -0,0 +1,21 @@
+# Next.js template
+
+This is a Next.js template with shadcn/ui.
+
+## Adding components
+
+To add components to your app, run the following command:
+
+```bash
+npx shadcn@latest add button
+```
+
+This will place the ui components in the `components` directory.
+
+## Using components
+
+To use the components in your app, import them as follows:
+
+```tsx
+import { Button } from "@/components/ui/button";
+```