test(server): runs leave no residue — auto-cleanup for every resource the suite creates

Symptom: repeated full-suite runs poisoned the dev database with
leaked rows (duplicate Prefs Scope libraries, colliding device names,
saved-filter name conflicts on rerun) because tests created rows but
never deleted them, and stale-binary runs left rows the new cleanup
could not match.

- test_helpers: library creation now registers t.Cleanup DELETE (the
  leak root cause — createTestLibraryWithFolder never cleaned up).
  Suite-wide cleanup passes for libraries/collections/devices/
  saved-filters run both at setup (pre-pass against legacy residue)
  and in t.Cleanup (no per-run residue). Preserve the admin's real
  libraries; delete only convention-named test rows.
- setup seeds canonical system collections every run keyed on
  query_type (idempotent — heals renames/stale tombstones), moved out
  of the preserved-admin branch so it runs for every suite start.
- dashboard_integration: scope-testing library renamed into the
  test-row convention; ordering assertions on the restored
  "Want to Read" collection preserved.
- filters_test: filter names moved into the convention (rerun-safe —
  name-uniqueness 409 no longer trips second runs); five  .(string)
  type assertions panic-proofed with require.True guards (a panic here
  used to kill the whole test process mid-run, which is why a stack of
  "never ran" failures surfaced at once later).
- device_test: device names moved into the convention (ILIKE %test%
  hit them; duplicate-device-name conflicts gone).

cmd/server/tests/test_helpers_test.go

@@ -295,6 +295,26 @@ func createDefaultCollectionsForUser(t *testing.T, db *database.Queries, userID
 	}
 
 	for _, col := range defaultCollections {
+		// Idempotent by the STABLE identity (user + query_type): existing
+		// rows (renamed, tombstoned) heal to canonical metadata in place;
+		// insert only when the query type has no row. A blind insert here
+		// hit UNIQUE(user_id, name) on every preserved-admin rerun.
+		existing, gerr := db.GetSystemCollectionByQueryType(ctx, database.GetSystemCollectionByQueryTypeParams{
+			UserID:    userID,
+			QueryType: pgtype.Text{String: col.QueryType, Valid: true},
+		})
+		if gerr == nil {
+			_, uerr := db.RestoreSystemCollectionRow(ctx, database.RestoreSystemCollectionRowParams{
+				ID:          existing.ID,
+				Name:        col.Name,
+				Description: pgtype.Text{String: col.Description, Valid: true},
+				Icon:        pgtype.Text{String: col.Icon, Valid: true},
+				Color:       pgtype.Text{String: col.Color, Valid: true},
+				Priority:    pgtype.Int4{Int32: col.Priority, Valid: true},
+			})
+			require.NoError(t, uerr, "Should restore default collection: "+col.Name)
+			continue
+		}
 		_, err := db.CreateSystemCollection(ctx, database.CreateSystemCollectionParams{
 			UserID:          userID,
 			Name:            col.Name,
@@ -627,9 +647,41 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 		require.NoError(t, cerr, "Failed to create admin test user")
 		adminUUID, err = uuid.FromBytes(adminUser.ID.Bytes[:])
 		require.NoError(t, err, "Failed to parse admin user UUID")
-		// Default collections are created exactly once per user; the
-		// preserved dev admin already has its set from the first run.
-		createDefaultCollectionsForUser(t, queries, pgtype.UUID{Bytes: adminUUID, Valid: true})
+	}
+	// The canonical system-collection set is ensured on EVERY run: the
+	// helper is idempotent by (user, query_type) and heals tombstoned or
+	// renamed rows, so suite runs can't accumulate naming-drift copies.
+	createDefaultCollectionsForUser(t, queries, pgtype.UUID{Bytes: adminUUID, Valid: true})
+
+	// Delete test-created COLLECTIONS (names containing "test"): without
+	// this, every suite run leaves its collections behind and the next
+	// run's creates die on UNIQUE(user_id, name) — the "collections
+	// 500-panic" rot. System collections are skipped (permanent rows).
+	// Same convention as the library pass: names containing "test".
+	adminColls, cerr := queries.GetCollectionsByUser(ctx, pgtype.UUID{Bytes: adminUUID, Valid: true})
+	if cerr == nil {
+		for _, coll := range adminColls {
+			if !coll.IsSystemCollection.Bool && strings.Contains(strings.ToLower(coll.Name), "test") {
+				queries.DeleteCollection(ctx, coll.ID)
+			}
+		}
+	}
+
+	// Same passes for test DEVICES (identifier/name containing "test")
+	// and test SAVED FILTERS (name containing "test"): both accumulated
+	// across runs and poisoned later runs (duplicate identifiers, 409s,
+	// non-empty "initially empty" assertions).
+	_, derr := dbPool.Exec(ctx,
+		"DELETE FROM devices WHERE user_id = $1 AND (device_identifier ILIKE '%test%' OR device_name ILIKE '%test%')",
+		adminUUID)
+	if derr != nil {
+		t.Logf("device cleanup failed: %v", derr)
+	}
+	_, ferr := dbPool.Exec(ctx,
+		"DELETE FROM saved_filters WHERE user_id = $1 AND name ILIKE '%test%'",
+		adminUUID)
+	if ferr != nil {
+		t.Logf("saved-filter cleanup failed: %v", ferr)
 	}
 
 	// Create fresh regular test user
@@ -680,6 +732,17 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 			}
 		}
 
+		// Same pass for test-created COLLECTIONS (the "collections
+		// 500-panic" rot: they lingered forever and poisoned later runs).
+		adminColls, cerr := queries.GetCollectionsByUser(ctx, pgtype.UUID{Bytes: adminUUID, Valid: true})
+		if cerr == nil {
+			for _, coll := range adminColls {
+				if !coll.IsSystemCollection.Bool && strings.Contains(strings.ToLower(coll.Name), "test") {
+					queries.DeleteCollection(ctx, coll.ID)
+				}
+			}
+		}
+
 		if err := setup.Close(); err != nil {
 			t.Errorf("Failed to cleanup test server: %v", err)
 		}