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/infrastructure/adapters/calendar_storage_adapter.rs

@@ -47,7 +47,7 @@ impl CalendarStoragePort for CalendarStorageAdapter {
     async fn create_calendar(
         &self,
         dto: CreateCalendarDto,
-        owner_id: &str,
+        owner_id: Uuid,
     ) -> Result<CalendarDto, DomainError> {
         let calendar = Calendar::new(dto.name, owner_id.to_string(), dto.description, dto.color)?;
 
@@ -117,7 +117,7 @@ impl CalendarStoragePort for CalendarStorageAdapter {
 
     async fn list_calendars_by_owner(
         &self,
-        owner_id: &str,
+        owner_id: Uuid,
     ) -> Result<Vec<CalendarDto>, DomainError> {
         let calendars = self
             .calendar_repository
@@ -128,7 +128,7 @@ impl CalendarStoragePort for CalendarStorageAdapter {
 
     async fn list_calendars_shared_with_user(
         &self,
-        user_id: &str,
+        user_id: Uuid,
     ) -> Result<Vec<CalendarDto>, DomainError> {
         let calendars = self
             .calendar_repository
@@ -152,7 +152,7 @@ impl CalendarStoragePort for CalendarStorageAdapter {
     async fn check_calendar_access(
         &self,
         calendar_id: &str,
-        user_id: &str,
+        user_id: Uuid,
     ) -> Result<bool, DomainError> {
         let uuid = Uuid::parse_str(calendar_id).map_err(|_| {
             DomainError::new(
@@ -172,7 +172,7 @@ impl CalendarStoragePort for CalendarStorageAdapter {
     async fn share_calendar(
         &self,
         calendar_id: &str,
-        user_id: &str,
+        user_id: Uuid,
         access_level: &str,
     ) -> Result<(), DomainError> {
         let uuid = Uuid::parse_str(calendar_id).map_err(|_| {
@@ -191,7 +191,7 @@ impl CalendarStoragePort for CalendarStorageAdapter {
     async fn remove_calendar_sharing(
         &self,
         calendar_id: &str,
-        user_id: &str,
+        user_id: Uuid,
     ) -> Result<(), DomainError> {
         let uuid = Uuid::parse_str(calendar_id).map_err(|_| {
             DomainError::new(