test(handlers): add missing DB-error tests for Record and SessionSearch

Cherry-pick of PR #1094 (test/delegate-record-db-errors) test functions
onto current staging. Original PR was stale (branched before 4bdb10b5).
Closes #1094.

New tests:
- TestSessionSearch_DBError: verifies SessionSearch returns 500 when
  the DB query returns an error
- TestDelegationRecord_DBInsertFails: verifies Record returns 500 when
  the activity_logs INSERT fails

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

workspace-server/internal/handlers/activity_test.go

@@ -63,6 +63,31 @@ func TestSessionSearchReturnsActivityAndMemory(t *testing.T) {
 	}
 }
 
+func TestSessionSearch_DBError(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	handler := NewActivityHandler(broadcaster)
+
+	mock.ExpectQuery("WITH session_items AS").
+		WillReturnError(context.DeadlineExceeded)
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("GET", "/workspaces/ws-123/session-search?q=test", bytes.NewBufferString(""))
+	c.Request.Header.Set("Content-Type", "application/json")
+	c.Params = gin.Params{{Key: "id", Value: "ws-123"}}
+
+	handler.SessionSearch(c)
+
+	if w.Code != http.StatusInternalServerError {
+		t.Errorf("expected 500 on DB error, got %d", w.Code)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet sqlmock expectations: %v", err)
+	}
+}
+
 // ---------- Activity List source filter ----------
 
 func TestActivityList_SourceCanvas(t *testing.T) {

workspace-server/internal/handlers/delegation_test.go

@@ -543,6 +543,33 @@ func TestDelegationRecord_RejectsInvalidUUID(t *testing.T) {
 	}
 }
 
+func TestDelegationRecord_DBInsertFails(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	wh := NewWorkspaceHandler(broadcaster, nil, "http://localhost:8080", t.TempDir())
+	h := NewDelegationHandler(wh, broadcaster)
+
+	mock.ExpectExec("INSERT INTO activity_logs").
+		WillReturnError(fmt.Errorf("connection refused"))
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "550e8400-e29b-41d4-a716-446655440000"}}
+	body := `{"target_id":"550e8400-e29b-41d4-a716-446655440001","task":"hello","delegation_id":"del-xyz"}`
+	c.Request = httptest.NewRequest("POST", "/delegations/record", bytes.NewBufferString(body))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	h.Record(c)
+
+	if w.Code != http.StatusInternalServerError {
+		t.Errorf("expected 500 on DB insert failure, got %d", w.Code)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet expectations: %v", err)
+	}
+}
+
 func TestDelegationUpdateStatus_CompletedInsertsResultRow(t *testing.T) {
 	mock := setupTestDB(t)
 	setupTestRedis(t)