Make loop engineering resumable across agent hosts

[cheshirecode]

What

• Keep active loop invocations running until completion or a real blocker.
• Add SHA-bound successor state for intervention recovery while preserving cumulative budget.
• Document honest recurrence behavior for Codex, Claude Code, and Cursor.
• Distinguish malformed CLI use (exit 2) from valid commands rejected by the state contract (exit 3).
• Clarify terminal-cycle accounting with finish --consume.

Verification evidence

• Skill Creator validation passed for loop-engineering and evidence-gate.
• Focused unit tests: 15 passed.
• Static repository checks: 10 passed.
• Full repository checks: 65 passed.
• Ruff formatting and lint checks passed.
• git diff --check passed.
• Independent Claude and OpenCode cold retests recommended publishing faed420 as-is.

Risks / follow-ups

The annotate session-ownership observation is non-blocking and recorded separately. The retest harness now allocates collision-proof temporary directories.