New learning-routes.js: scenario start/attempt-state/hint (sequential reveal, 409 once
exhausted, policy-aware under an active assessment), GET /api/curriculum/state (rule-driven,
alongside the unchanged /api/curriculum/path), assessments list/start/active/detail/submit,
GET /api/capstone, GET /api/achievements, GET /api/attempts/recent.
/api/progress/record now routes through attempts.recordValidation instead of a flat insert,
and, on a pass, checks curriculum/capstone achievement consequences and, if the scenario is
part of an active assessment, updates that session (assessment context is derived entirely
server-side from assessment_session_scenarios, never from anything the client asserts).
Gateway changes: two new relay routes (/lab/:token/api/scenarios/:id/start and .../hint,
mirroring the existing validate/answer pattern - pure Platform API operations, the Lab has no
attempt/hint concept) and a response rewrite on GET /lab/:token/api/scenarios/:id that strips
the Lab's own hints array (replacing it with a bare hint_count) so progressive reveal is
actually server-gated instead of just UI-collapsed - the Lab image's bytes stay untouched;
standalone/single-container dev mode never goes through the Gateway and keeps the full array
unaffected.
