- Removed old logic that created a single story/feature task on accept
- Accept now iterates all Essentials under the Proposal
- Each Essential.type maps to a story/* task (feature/improvement/refactor)
- All tasks created in a single transaction
- Added ProposalAcceptResponse and GeneratedTaskSummary schemas
- Proposal must have at least one Essential to be accepted
- No longer writes to deprecated feat_task_id field