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/common/stubs.rs

@@ -74,10 +74,6 @@ impl FileReadPort for StubFileReadPort {
         Ok(Vec::new())
     }
 
-    async fn get_file_content(&self, _id: &str) -> Result<Vec<u8>, DomainError> {
-        Ok(Vec::new())
-    }
-
     async fn get_file_stream(
         &self,
         _id: &str,
@@ -96,10 +92,6 @@ impl FileReadPort for StubFileReadPort {
         Ok(Box::new(empty_stream))
     }
 
-    async fn get_file_mmap(&self, _id: &str) -> Result<Bytes, DomainError> {
-        Ok(Bytes::new())
-    }
-
     async fn get_file_path(&self, _id: &str) -> Result<StoragePath, DomainError> {
         Ok(StoragePath::from_string("/"))
     }
@@ -525,10 +517,6 @@ impl FileRetrievalUseCase for StubFileRetrievalUseCase {
         Ok(Vec::new())
     }
 
-    async fn get_file_content(&self, _id: &str) -> Result<Vec<u8>, DomainError> {
-        Ok(Vec::new())
-    }
-
     async fn get_file_stream(
         &self,
         _id: &str,
@@ -697,20 +685,6 @@ impl DedupPort for StubDedupPort {
         None
     }
 
-    async fn read_blob(&self, _hash: &str) -> Result<Vec<u8>, DomainError> {
-        Err(DomainError::internal_error(
-            "DedupService",
-            "DedupService not initialized",
-        ))
-    }
-
-    async fn read_blob_bytes(&self, _hash: &str) -> Result<Bytes, DomainError> {
-        Err(DomainError::internal_error(
-            "DedupService",
-            "DedupService not initialized",
-        ))
-    }
-
     async fn read_blob_stream(
         &self,
         _hash: &str,