perf: findings 6.1, 6.2, 2.6 — async Argon2, moka cache, full streaming migration

- 6.1: PasswordHasherPort now async_trait with spawn_blocking for Argon2
- 6.2: OIDC pending maps migrated from std::sync::Mutex to moka::sync::Cache with TTL
- 2.6: All file download paths migrated to 64KB streaming (get_file_stream / read_blob_stream)
  - WOPI, dedup, batch ZIP, file_retrieval_service consumers migrated
  - WebDAV COPY uses zero-copy dedup (copy_file)
  - Removed dead code: get_file_content, get_file_mmap, read_blob, read_blob_bytes
    from traits, impls, stubs, and mocks (18 files touched)

src/application/services/trash_service_test.rs

@@ -142,10 +142,6 @@ impl FileReadPort for MockFileRepository {
         Ok(vec![])
     }
 
-    async fn get_file_content(&self, _id: &str) -> std::result::Result<Vec<u8>, DomainError> {
-        Ok(vec![])
-    }
-
     async fn get_file_stream(
         &self,
         _id: &str,
@@ -168,10 +164,6 @@ impl FileReadPort for MockFileRepository {
         unimplemented!()
     }
 
-    async fn get_file_mmap(&self, _id: &str) -> std::result::Result<Bytes, DomainError> {
-        unimplemented!()
-    }
-
     async fn get_file_path(&self, _id: &str) -> std::result::Result<StoragePath, DomainError> {
         unimplemented!()
     }