fix(dag): close orchestration acceptance gaps

[LeXwDeX]

Summary

• add bounded root-only workflow result retrieval with target-bound cursors
• make wake previews recoverable without unbounded prompt injection
• enforce task/workflow leaf boundaries for DAG child sessions
• require workflow permission checks before every action
• bind implementation reviews to verification PASS and implementation fingerprints
• prevent standard and deep workflows from completing without an accepted diff review

Verification

• DAG suite: 425 pass, 0 fail
• focused acceptance/spec suite: 104 pass, 0 fail
• repository typecheck: 29/29 packages
• lint: 4852 warnings, 0 errors (ratchet limit 4852)
• generated client and SDK checks: clean
• OpenSpec strict validation: pass
• Standards review: 0 findings
• Spec review: 0 findings

Red-to-green evidence

• long node output was previously truncated with no supported retrieval path
• DAG child sessions could previously bypass the leaf boundary through task
• block reviews could previously consume stale or unverified implementation evidence
• standard mode verification failure could previously settle as completed

All four cases now have public-seam regression coverage.