Three fixes for phases getting stuck when a detail task crashes and is retried:
1. detailPhase mutation (architect.ts): clean up orphaned pending/in_progress
detail tasks before creating new ones, preventing duplicates at the source
2. orchestrator recovery: detect and complete stale duplicate planning tasks
(same category+phase, one completed, one pending)
3. ensureBranch: catch "already exists" TOCTOU race instead of blocking phase
346d62ef8d