[johnnyhuy]

Part of #85
Closes #114

What changed: the catalog no longer defines the same groups and guest user twice. examples/ is now the single source for group:default/readers, group:default/developers, group:default/admins and user:default/guest, as documented in docs/demo-baseline.md. Deleted default-catalog/groups.yaml (only duplicates), removed the three guest User entries from default-catalog/users.yaml (kept the unique johnnyhuy user, still a developers member via examples), and dropped the ./groups.yaml target from default-catalog/catalog-info.yaml. The unique echohello organisation group in organizations.yaml is untouched. Config-only slice, no code or visual change.

How it was verified:

• mise run install - passed
• mise run lint - passed (packages/backend 1 file, permission module 3 files, theme 1 file, plausible 8 files, packages/app 46 files, no errors)
• mise run test - passed: 3 suites passed, 1 skipped, 22 tests passed, 1 skipped (unchanged from main)
• Duplicate scan over default-catalog/.yaml and examples/**/.yaml (excluding template skeletons): 73 unique entity refs, zero duplicates. Before this change the same refs collided across the two trees.
• mise run dev - frontend on localhost:3000 returned 200 and the backend catalog log showed zero conflicting entityRef warnings (the previous run logged 12 for these refs). Processing group:default/readers and Processing user:default/guest each appear once per cycle. Frontend-only config slice in effect, but the backend was booted because catalog loading is backend behaviour. mise run build (Docker image) was not run as no backend code or packaging changed.

Proof:
Capture method: agent-browser snapshot succeeded, PNG capture was blocked. The agent-browser screenshot command hung and was terminated, so no PNG is attached (same block as the #113 run). The live snapshot is the behaviour proof: signed in as guest, opened /catalog?filters[kind]=group, and the table listed Admins, Developers and Readers exactly once each, served from the deduped catalog with no conflict warnings in the backend log.

Known gaps and follow-ups:

• The parent epic Release demo-ready developer portal experience #85 stays open.
• Johnny: no design or taste call was made here. The Gumroad-style landing page look under Ship public showcase landing page with Gumroad-style direction #84 is still yours to direct.