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/domain/repositories/session_repository.rs

@@ -1,5 +1,6 @@
 use crate::common::errors::DomainError;
 use crate::domain::entities::session::Session;
+use uuid::Uuid;
 
 #[derive(Debug, thiserror::Error)]
 pub enum SessionRepositoryError {
@@ -33,7 +34,7 @@ pub trait SessionRepository: Send + Sync + 'static {
     async fn create_session(&self, session: Session) -> SessionRepositoryResult<Session>;
 
     /// Gets a session by ID
-    async fn get_session_by_id(&self, id: &str) -> SessionRepositoryResult<Session>;
+    async fn get_session_by_id(&self, id: Uuid) -> SessionRepositoryResult<Session>;
 
     /// Gets a session by refresh token
     async fn get_session_by_refresh_token(
@@ -42,14 +43,14 @@ pub trait SessionRepository: Send + Sync + 'static {
     ) -> SessionRepositoryResult<Session>;
 
     /// Gets all sessions for a user
-    async fn get_sessions_by_user_id(&self, user_id: &str)
+    async fn get_sessions_by_user_id(&self, user_id: Uuid)
     -> SessionRepositoryResult<Vec<Session>>;
 
     /// Revokes a specific session
-    async fn revoke_session(&self, session_id: &str) -> SessionRepositoryResult<()>;
+    async fn revoke_session(&self, session_id: Uuid) -> SessionRepositoryResult<()>;
 
     /// Revokes all sessions for a user
-    async fn revoke_all_user_sessions(&self, user_id: &str) -> SessionRepositoryResult<u64>;
+    async fn revoke_all_user_sessions(&self, user_id: Uuid) -> SessionRepositoryResult<u64>;
 
     /// Deletes expired sessions
     async fn delete_expired_sessions(&self) -> SessionRepositoryResult<u64>;