Mockup Workspace Implementation Plan

Follow executing-plans in this session.

Goal: Deliver Mockup submenu, shared screen artifacts, Sitemap, use-case Page flows and Screen Listing/detail. Architecture: Go SSR routes + filesystem catalog + SVG image-card editor; source graphs separate from atomically saved revision documents. Spec: ../specs/2026-10-31-mockup-workspace-design.md

• [x] Build artifacts from canonical source with explicit draft/provenance and existing references; validate all IDs/assets.
• [x] Test and implement mockup catalog, graph loading/validation, atomic save/conflict/history/restore and safe asset endpoints.
• [x] Add sidebar submenu, catalog/detail, oriented SVG editor, mapping/properties, undo/redo, grid/zoom, reload and revision UI; protect live edits.
• [x] Run Go/race/vet, artifact checks and browser regressions with temporary data; inspect screenshots and serve main8099.
• [x] Document folder/schema/update workflow, record tests/checkpoint and close T-418 when verified.

Do not overwrite earlier Use-case audit changes or existing saved graphs. Do not approve product use cases or fabricate confirmed screen-step mappings.

Verified 2026-10-31T11:21:44+07:00: artifacts and Go/race/vet passed; browser 43+70+25+9=147 passed; main 8099 GET smoke passed. C-029, R-021, P-014; T-418 Done with human review pending. No worktree or project copy was created.