refactor: extract shared memory service

surfsense_backend/app/services/memory/schemas.py

@@ -0,0 +1,23 @@
+"""Structured output schemas for memory extraction."""
+
+from __future__ import annotations
+
+from typing import Literal
+
+from pydantic import BaseModel, Field
+
+
+class MemoryExtractionDecision(BaseModel):
+    """Structured extraction result; avoids string sentinel parsing."""
+
+    action: Literal["no_update", "save"] = Field(
+        description="Choose no_update when nothing durable should be saved; choose save otherwise."
+    )
+    reason: str | None = Field(
+        default=None,
+        description="Short reason for no_update, or brief summary of the memory update.",
+    )
+    updated_memory: str | None = Field(
+        default=None,
+        description="The full updated markdown memory document when action is save.",
+    )