feat: production release with React SPA, file attachments, and deploy tooling

Backend:
- Add file_handlers.go: presigned upload/download for item attachments
- Add item_files.go: item file and thumbnail DB operations
- Add migration 011: item_files table and thumbnail_key column
- Update items/projects/relationships DB with extended field support
- Update routes: React SPA serving from web/dist, file upload endpoints
- Update auth handlers and middleware for cookie + bearer token auth
- Remove Go HTML templates (replaced by React SPA)
- Update storage client for presigned URL generation

Frontend:
- Add TagInput component for tag/keyword entry
- Add SVG assets for Silo branding and UI icons
- Update API client and types for file uploads, auth, extended fields
- Update AuthContext for session-based auth flow
- Update LoginPage, ProjectsPage, SchemasPage, SettingsPage
- Fix tsconfig.node.json

Deployment:
- Update config.prod.yaml: single-binary SPA layout at /opt/silo
- Update silod.service: ReadOnlyPaths for /opt/silo
- Add scripts/deploy.sh: build, package, ship, migrate, start
- Update docker-compose.yaml and Dockerfile
- Add frontend-spec.md design document

go.mod

@@ -9,8 +9,8 @@ require (
 	github.com/go-chi/chi/v5 v5.0.12
 	github.com/go-chi/cors v1.2.1
 	github.com/go-ldap/ldap/v3 v3.4.12
+	github.com/google/uuid v1.6.0
 	github.com/jackc/pgx/v5 v5.5.4
-	github.com/justinas/nosurf v1.2.0
 	github.com/minio/minio-go/v7 v7.0.66
 	github.com/rs/zerolog v1.32.0
 	github.com/sahilm/fuzzy v0.1.1
@@ -24,7 +24,6 @@ require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/go-asn1-ber/asn1-ber v1.5.8-0.20250403174932-29230038a667 // indirect
 	github.com/go-jose/go-jose/v4 v4.1.3 // indirect
-	github.com/google/uuid v1.6.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
 	github.com/jackc/puddle/v2 v2.2.1 // indirect