feat: Add id and custom_metadata fields to MemoryEntry

PiperOrigin-RevId: 833581243

src/google/adk/memory/memory_entry.py

@@ -15,10 +15,12 @@
 
 from __future__ import annotations
 
+from typing import Any
 from typing import Optional
 
 from google.genai import types
 from pydantic import BaseModel
+from pydantic import Field
 
 
 class MemoryEntry(BaseModel):
@@ -27,6 +29,12 @@ class MemoryEntry(BaseModel):
   content: types.Content
   """The main content of the memory."""
 
+  custom_metadata: dict[str, Any] = Field(default_factory=dict)
+  """Optional custom metadata associated with the memory."""
+
+  id: Optional[str] = None
+  """The unique identifier of the memory."""
+
   author: Optional[str] = None
   """The author of the memory."""