fix(mypy): resolve type issues in MongoDB, batches, and auth providers (#3933)

Fixes mypy type errors in provider utilities:
- MongoDB: Fix AsyncMongoClient parameters, use async iteration for
cursor
- Batches: Handle memoryview|bytes union for file decoding
- Auth: Add missing imports, validate JWKS URI, conditionally pass
parameters

Fixes 11 type errors. No functional changes.

src/llama_stack/providers/inline/batches/reference/batches.py

@@ -358,7 +358,11 @@ class ReferenceBatchesImpl(Batches):
 
         # TODO(SECURITY): do something about large files
         file_content_response = await self.files_api.openai_retrieve_file_content(batch.input_file_id)
-        file_content = file_content_response.body.decode("utf-8")
+        # Handle both bytes and memoryview types
+        body = file_content_response.body
+        if isinstance(body, memoryview):
+            body = bytes(body)
+        file_content = body.decode("utf-8")
         for line_num, line in enumerate(file_content.strip().split("\n"), 1):
             if line.strip():  # skip empty lines
                 try:

src/llama_stack/providers/utils/kvstore/mongodb/mongodb.py

@@ -30,14 +30,13 @@ class MongoDBKVStoreImpl(KVStore):
 
     async def initialize(self) -> None:
         try:
-            conn_creds = {
-                "host": self.config.host,
-                "port": self.config.port,
-                "username": self.config.user,
-                "password": self.config.password,
-            }
-            conn_creds = {k: v for k, v in conn_creds.items() if v is not None}
-            self.conn = AsyncMongoClient(**conn_creds)
+            # Pass parameters explicitly to satisfy mypy - AsyncMongoClient doesn't accept **dict
+            self.conn = AsyncMongoClient(
+                host=self.config.host if self.config.host is not None else None,
+                port=self.config.port if self.config.port is not None else None,
+                username=self.config.user if self.config.user is not None else None,
+                password=self.config.password if self.config.password is not None else None,
+            )
         except Exception as e:
             log.exception("Could not connect to MongoDB database server")
             raise RuntimeError("Could not connect to MongoDB database server") from e
@@ -79,4 +78,8 @@ class MongoDBKVStoreImpl(KVStore):
         end_key = self._namespaced_key(end_key)
         query = {"key": {"$gte": start_key, "$lt": end_key}}
         cursor = self.collection.find(query, {"key": 1, "_id": 0}).sort("key", 1)
-        return [doc["key"] for doc in cursor]
+        # AsyncCursor requires async iteration
+        result = []
+        async for doc in cursor:
+            result.append(doc["key"])
+        return result