feat: add memory management actions and local filters in memory settings (#1467)

* Add MVP memory management actions

* Fix memory settings locale coverage

* Polish memory management interactions

* Add memory search and type filters

* Refine memory settings review feedback

* docs: simplify memory settings review setup

* fix: restore memory updater compatibility helpers

* fix: address memory settings review feedback

* docs: soften memory sample review wording

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
Co-authored-by: JeffJiang <for-eleven@hotmail.com>

backend/tests/test_memory_router.py

@@ -0,0 +1,72 @@
+from unittest.mock import patch
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from app.gateway.routers import memory
+
+
+def _sample_memory(facts: list[dict] | None = None) -> dict:
+    return {
+        "version": "1.0",
+        "lastUpdated": "2026-03-26T12:00:00Z",
+        "user": {
+            "workContext": {"summary": "", "updatedAt": ""},
+            "personalContext": {"summary": "", "updatedAt": ""},
+            "topOfMind": {"summary": "", "updatedAt": ""},
+        },
+        "history": {
+            "recentMonths": {"summary": "", "updatedAt": ""},
+            "earlierContext": {"summary": "", "updatedAt": ""},
+            "longTermBackground": {"summary": "", "updatedAt": ""},
+        },
+        "facts": facts or [],
+    }
+
+
+def test_clear_memory_route_returns_cleared_memory() -> None:
+    app = FastAPI()
+    app.include_router(memory.router)
+
+    with patch("app.gateway.routers.memory.clear_memory_data", return_value=_sample_memory()):
+        with TestClient(app) as client:
+            response = client.delete("/api/memory")
+
+    assert response.status_code == 200
+    assert response.json()["facts"] == []
+
+
+def test_delete_memory_fact_route_returns_updated_memory() -> None:
+    app = FastAPI()
+    app.include_router(memory.router)
+    updated_memory = _sample_memory(
+        facts=[
+            {
+                "id": "fact_keep",
+                "content": "User likes Python",
+                "category": "preference",
+                "confidence": 0.9,
+                "createdAt": "2026-03-20T00:00:00Z",
+                "source": "thread-1",
+            }
+        ]
+    )
+
+    with patch("app.gateway.routers.memory.delete_memory_fact", return_value=updated_memory):
+        with TestClient(app) as client:
+            response = client.delete("/api/memory/facts/fact_delete")
+
+    assert response.status_code == 200
+    assert response.json()["facts"] == updated_memory["facts"]
+
+
+def test_delete_memory_fact_route_returns_404_for_missing_fact() -> None:
+    app = FastAPI()
+    app.include_router(memory.router)
+
+    with patch("app.gateway.routers.memory.delete_memory_fact", side_effect=KeyError("fact_missing")):
+        with TestClient(app) as client:
+            response = client.delete("/api/memory/facts/fact_missing")
+
+    assert response.status_code == 404
+    assert response.json()["detail"] == "Memory fact 'fact_missing' not found."