Adds the merchant authoring flow on top of the existing recommender:
- POST /tna/draft: propose a TNA for a no-TNA order, with optional template
override + fabric-lead-time override (recommender extended for both).
- PUT /tna/recommend/{key}/schedule: persist planner date/owner edits (frozen
once accepted); sets edited flag.
- POST /tna/push/{key}: push an approved plan's template to Stitch, gated on
Template-Readiness — returns blocked + missing tasks when the tenant isn't
seeded (no silent failure). Distinct path avoids the /{decision} route clash.
- TnaRecommendation gains pcd_date/edited/stitch_template_id/push_status/
push_detail (idempotent migration + boot self-heal in services/tna_authoring).
- Frontend: TnaCreate page (proposal + template picker + fabric-lead-time input +
editable milestone table + approve→push with readiness gate), wired from the
"Create TNA" action on the no-TNA cards.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
