fix: close Academy authoring workflow gaps

[botsarefuture]

Purpose

Close the gaps found by the roadmap truth audit before continuing the educational media pipeline.

What changed

• adds blank lesson and course creation in Admin Academy
• adds explicit next-revision actions for published lessons and courses
• versions course records and pins exact lesson revisions at publication
• returns Academy roles immediately after registration and login
• adds a guarded, non-destructive legacy course-index migration
• corrects stale roadmap statuses and moves content expansion ahead of the Coach
• records Interactive Practice in backlog
• restores 44px Admin Academy touch targets

Validation

• npm run check:version
• npm test (25 passing)
• PYTHONPATH=server python3 -m unittest discover -s server -p "test_*.py" (15 passing)
• npm run build
• clean Docker Compose staging workflow using separate author, reviewer, and publisher accounts
• verified lesson v1 remains pinned after lesson v2 publication, then course v2 resolves lesson v2
• verified public cache headers, role enforcement, migration guard, clean-volume rebuild, and 390px mobile layout

Migration

Before production creates a second course revision, run the guarded command documented in docs/academy-content-delivery.md. Existing course records become version 1; no content is deleted.

Known limitations

Educational media persistence and authoring remain Milestone 6 work.