- Update _make_valid_tree() in test_ai_tree_validator to use next_node_id
on action nodes (solution is a sibling, not a child)
- Fix test_dead_end_action_node → test_dead_end_decision_node (action nodes
don't have child-based dead ends; dead ends are decision nodes with no children)
- Add test_action_missing_next_node_id for the new validation rule
- Update BRANCH_DETAIL_JSON in test_ai_endpoints to use next_node_id pattern
- Update test_draft_trees.py to use "title" field for action/solution nodes
(tree_validation.py was updated this branch to require "title" not "action"/"solution")
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Implements the complete AI flow builder feature using a guided 4-stage
wizard (Foundation → Scaffold → Branch Detail → Review & Assemble).
AI assists at bounded points using Claude Haiku for cost-efficient
structured JSON generation (~$0.01-0.03/flow).
Backend: new models (ai_conversations, ai_usage), Alembic migration,
quota enforcement with billing anchor, Anthropic API integration with
prompt caching, tree validation, conversation CRUD with 24h TTL,
APScheduler cleanup job, 5 API endpoints, Pydantic schemas.
Frontend: TypeScript types, API client, Zustand store for wizard state,
7 components (modal, step indicator, foundation form, branch selector,
branch detail view, tree preview, quota display), MyTreesPage integration
with "Build with AI" button (hidden when AI not configured).
Tests: 14 validator unit tests + 11 endpoint integration tests with
mocked Anthropic (zero real API spend). All 25 tests passing.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
