perf: migrate all user/session/auth IDs from VARCHAR(36) to native UUID

- Schema: all ~15 VARCHAR(36) columns → UUID with DEFAULT gen_random_uuid()
- Domain entities: User, Session, DeviceCode, AppPassword, Share → id: Uuid
- DTOs: CurrentUser.id → Uuid (API boundary DTOs keep String for JSON)
- Auth middleware: parse JWT claims.sub (String) → Uuid at boundary
- All repository traits, port traits, service impls updated end-to-end
- Handlers: pass Uuid by value (Copy, 16 bytes) instead of String refs
- Settings chain: updated_by column → Uuid (was text, caused setup crash)
- Removed ~650 lines of String↔Uuid conversion boilerplate
- Eliminates per-request heap allocations for ID cloning
- 16-byte binary comparison vs 36-byte string comparison in all queries
- Native UUID indexing in PostgreSQL (btree on 16 bytes vs 36-char text)

85 files changed, 1090 insertions(+), 1739 deletions(-)

src/interfaces/api/handlers/photos_handler.rs

@@ -31,7 +31,7 @@ pub async fn list_photos(
     auth_user: AuthUser,
     Query(params): Query<PhotosQueryParams>,
 ) -> impl IntoResponse {
-    let user_id = &auth_user.id;
+    let user_id = auth_user.id;
     let limit = params.limit.unwrap_or(200).clamp(1, 500);
 
     let file_read = &state.repositories.file_read_repository;