Execute build chunks with auto-fix and structured feedback

Execute approved chunks in waves with failure escalation

Large features where chunked implementation avoids bloat + auto-escalation prevents silent failure.

• · description
• · plan (markdown)
• · waves (dependency-ordered chunks)
• · model tiers per chunk

• · per-chunk results (status/files changed)
• · findings (blockers/concerns/nits)
• · auto-fixes applied (cap 2)

• · agent() (Opus/Sonnet/Haiku)
• · parallel()
• · git (optional, for tests)

Workflow runtime; approved chunk plan; tests available if required; model tier escalation support

• · Blocker at attempt 2 cannot be auto-fixed (escalates to human)
• · Auto-fix attempt breaks unrelated tests
• · Concerns leaked into auto-fix when they should gate manually

• · Approved chunk plan gates execution
• · Dependency waves prevent out-of-order execution
• · Tier escalation (haiku→sonnet→opus) on failure
• · Auto-fix loop capped at 2 (blockers escalate to human)
• · Concerns gate (not auto-fixed)
• · Per-chunk atomic commits