Custom markup compatibility

The external Uiverse component catalog, dead subpanel and original assets were retired on 2026-10-25. Constructor-authored headers remain available through src/catalog/headers.ts and the native HeaderLibrary.tsx.

New content uses content.customComponent with the existing HTML, CSS, author, source URL/SHA and label configuration. src/utils/legacyCustomComponent.ts is the only production adapter that reads the historical content.uiverse key. It preserves the complete payload, gives an explicit new field precedence, removes the old key, and updates the old wrapper selector in historical CSS. It does not mutate the source object. Rendering still sanitizes HTML/CSS and destinations.

The adapter runs at project recovery, saved-block reading, published-document parsing, historical MCP document validation and standalone HTML export. Thus old projects, shared headers and blocks can be opened and saved under the current shape without a bulk rewrite of stored projects. Native MCP creation keeps its existing stricter native-component input contract.

The active word-loading animation retains its attribution and MIT notice in THIRD_PARTY_NOTICES.md; its provenance is not a component catalog dependency.

Other retired editor modules

A source import graph was checked across static imports, dynamic import(), require(), and barrel exports, then candidate names/paths were searched across source, server, tests and scripts. The following obsolete UI modules had no inbound references and were removed: old LeftSidebar and its five private drawers, StudioHeader, FloatingDrawer, its private FloatingToolbar, UserProfileSubpanel, useDraggableFloating, and FileTreeItem. The latter was the sole consumer of projectFileTree.ts, so that obsolete virtual-file generator was removed too. The active export dialog uses its current export implementation.

LegacyStylesDrawer remains: FloatingStylesDrawer actively renders it for callers without a project session. A legacy name alone is not deletion evidence.