Split large CMS files

Problem¶

A handful of CMS source files are large enough to harm reviewability and slow incremental edits:

• apps/cms/src/components/workarea/asset-manager.tsx — 810 lines (upload, listing, preview, dialogs all in one component).
• apps/cms/src/lib/db/seed.ts — 512 lines (multiple domains mixed).
• apps/cms/src/lib/export/renderers/widget-html/data-driven-widgets.ts — 448 lines (every data-driven widget renderer in one file).

None of these are broken; they are simply ripe for extraction.

Proposal¶

1. asset-manager.tsx → split into:
   • asset-manager/index.tsx (orchestrator).
   • asset-manager/upload.tsx.
   • asset-manager/listing.tsx.
   • asset-manager/preview.tsx.
   • asset-manager/dialogs.tsx.
   • Keep public API stable by re-exporting from the existing path.
2. seed.ts → split into seed/index.ts + per-domain files (seed/users.ts, seed/tenants.ts, seed/projects.ts, …). Orchestrator stays small and ordered.
3. data-driven-widgets.ts → split into data-driven-widgets/index.ts + one file per widget family; index re-exports the renderer map.

For each split:

• No behavior change.
• Tests stay green.
• Follow .cursor/rules/030 re component organization.

Acceptance criteria¶

• Each new file under ~250 lines.
• No public import path changes for consumers (verify via rg sweep).
• Existing tests pass without modification.
• npm run check passes.

Out of scope¶

• Behavioral changes (UI tweaks, seed data adjustments, renderer fixes).
• LMS file-size review (separate follow-up if needed).

Notes / decisions log¶

• 2026-05-24: Ticket created from monorepo audit.
• 2026-05-25: Implemented as one PR. seed-fixtures.ts unchanged; preview stays in asset-preview-dialog.tsx. Added seed/seed-data.ts shared with test/e2e/api-v1/helpers.ts. Added download-source-file export unit tests.