refactor: remove serde from domain entities for Clean Architecture compliance

- Remove Serialize/Deserialize from File, Folder, Session, User, Contact entities
- Create contact_persistence_dto.rs for JSONB persistence in infrastructure layer
- Update contact_pg_repository to use persistence DTOs
- Fix dependency on zip crate (downgrade from 7.2.0 to 2.1.0)
- Fix unused variable warnings in main.rs
- Move PathService import from domain to infrastructure
- Add missing fields to CoreServices and RepositoryServices
- Create proper service initialization in main.rs

Clean Architecture improvements:
- Domain layer no longer depends on serde framework
- Persistence concerns isolated to infrastructure layer
- TokenClaims in auth_service.rs is only exception (required for JWT)

src/application/adapters/webdav_adapter.rs

@@ -685,7 +685,7 @@ impl WebDavAdapter {
                 },
                 Ok(Event::Text(e)) => {
                     if current_prop.is_some() {
-                        current_text.push_str(&e.unescape().unwrap_or_default());
+                        current_text.push_str(&e.decode().unwrap_or_default());
                     }
                 },
                 Ok(Event::End(ref e)) => {
@@ -879,7 +879,7 @@ impl WebDavAdapter {
                 },
                 Ok(Event::Text(e)) => {
                     if in_owner {
-                        owner_text.push_str(&e.unescape().unwrap_or_default());
+                        owner_text.push_str(&e.decode().unwrap_or_default());
                     }
                 },
                 Ok(Event::End(ref e)) => {