test(dashboard): align test seed naming with the canonical Title-case set + fix stale expectations

The test helper createDefaultCollectionsForUser carried its own
kebab-case copy of the default system collections — drifted from the
canonical Title-case list the registration seed and
RestoreSystemCollection use. Every suite run against the shared dev DB
re-created a kebab set beside the canonical one (the duplicate sections
on the customize screens); the dev DB is cleaned and the helper now
uses the canonical list.

Two stale expectations corrected while re-running the suite:
TestGetSections_EndToEndFlow asserted the kebab ids (now asserts the
Title-case names — section ids ARE collection names), and
TestGetSections_MissingLibraryID expected a 400 the handler never
implemented — absent library_id is the All Libraries view by design
(now asserts 200 + aggregated sections).

cmd/server/tests/test_helpers_test.go

@@ -275,6 +275,10 @@ func uuidToPGType(u uuid.UUID) pgtype.UUID {
 // createDefaultCollectionsForUser creates the 4 default system collections for a user
 func createDefaultCollectionsForUser(t *testing.T, db *database.Queries, userID pgtype.UUID) {
 	ctx := context.Background()
+	// Canonical Title-case names — the same list the registration seed
+	// (CreateDefaultCollectionsForUser) and RestoreSystemCollection use.
+	// A stale kebab-case copy lived here once and duplicated every
+	// system collection in the shared dev DB.
 	defaultCollections := []struct {
 		Name        string
 		Description string
@@ -283,11 +287,11 @@ func createDefaultCollectionsForUser(t *testing.T, db *database.Queries, userID
 		QueryType   string
 		Priority    int32
 	}{
-		{"continue-reading", "Books you're currently reading (0 < progress < 1)", "📖", "#7aa2f7", "continue-reading", 1},
-		{"recently-added", "Newly added items to this library", "🆕", "#9ece6a", "recently-added", 2},
-		{"recently-read", "Books you've finished (progress >= 1)", "✅", "#e0af68", "recently-read", 3},
-		{"not-started", "Books you haven't read yet (progress = 0 or no record)", "📕", "#f7768e", "not-started", 4},
-		{"continue-series", "Next book in series you're reading", "📚", "#bb9af7", "continue-series", 5},
+		{"Continue Reading", "Books you're currently reading (0 < progress < 1)", "📖", "#7aa2f7", "continue-reading", 1},
+		{"Recently Added", "Newly added items to this library", "🆕", "#9ece6a", "recently-added", 2},
+		{"Recently Read", "Books you've finished (progress >= 1)", "✅", "#e0af68", "recently-read", 3},
+		{"Not Started", "Books you haven't read yet (progress = 0 or no record)", "📕", "#f7768e", "not-started", 4},
+		{"Continue Series", "Next book in series you're reading", "📚", "#bb9af7", "continue-series", 5},
 	}
 
 	for _, col := range defaultCollections {