feat(coord): §1e chore-claim gate with proactive queue enrichment

[otherness-app]

Summary

• Adds §1e-chore-gate to coord.md: when MEANINGFUL_PRS_THIS_SESSION==0 and COORD would claim a kind/chore item, the gate intercepts and injects a feature item first
• Gate scans docs/design/*.md for an unissued 🔲 Future item, creates a GitHub issue, and claims it instead
• Fallback: if no unissued Future items exist, writes meaningful_pr_guarantee_failed: true to state.json so SM §4b can diagnose
• MEANINGFUL_PRS_THIS_SESSION shell variable initialized at §1a startup and exported for ENG/QA to increment
• Fail-open on all errors (any exception → claim the original item)

Motivation

The session minimum meaningful-PR contract (design doc 35.x, issue-796) fires a [DEFECT] after the session ends with 0 meaningful PRs. This is retrospective. This PR makes the guarantee proactive: COORD cannot ship only chores unless there are literally no non-chore items available to generate from design docs.

Risk assessment

CRITICAL tier — modifies agents/phases/coord.md. Deploys to all projects on next session start.

• The gate is fail-open: any Python exception → PASS {ITEM_ID} → normal claim
• Tested: validate.sh PASSED, lint.sh PASSED
• The bash wrapper safely handles the REPLACE/PASS output parsing

Closes #882

Design doc

Updated docs/design/21-session-throughput.md: moved §1e chore-claim gate item from 🔲 Future to ✅ Present.

[NEEDS HUMAN: critical-tier-change]

Signed-off-by: otherness[bot] <otherness[bot]@users.noreply.github.com>

[otherness-app]

[NEEDS HUMAN: critical-tier-change] This PR modifies agents/phases/coord.md (CRITICAL tier). Deploys to all projects on next session startup. Requires human review before merge.

[otherness-app]

[AGENT SELF-REVIEW | sess-7af2b350 | otherness@103578b]

5-check CRITICAL-A self-review:

1. SPEC COMPLETENESS ✅ — All 6 Zone 1 obligations satisfied. O1: chore detection + MEANINGFUL_PRS check. O2: design doc scan + issue creation + REPLACE. O3: meaningful_pr_guarantee_failed fallback. O4: fail-open try/except at top level. O5: MEANINGFUL_PRS_THIS_SESSION initialized in §1a. O6: logged.

2. FAILURE MODE ANALYSIS ✅

   • No docs/design/ → scan skipped, fallback to chore claim
   • GitHub API unavailable → issue creation returns None → fallback
   • Item is not kind/chore → gate doesn't fire (PASS immediately)
   • state.json invalid → except Exception → PASS fallback
   • No kind/ labels on item → is_chore=False → gate doesn't fire (QA WRONG: fixed in second commit)

3. GLOBAL DEPLOYMENT CHECK ✅ — Gate wrapped in $(), output parsed with grep; if grep finds nothing, _GATE_ACTION is empty and if ['REPLACE' = ''] → false. New python block has outer try/except. Design docs path is relative — works in any project.

4. SIMPLICITY CHECK ✅ — Reuses existing patterns from §1c-guard (is_done_check, open_if_absent, design dir scan). ~150 lines but each line is necessary.

5. LONG-TERM VISION CHECK ✅ — Converts post-hoc defect detection to proactive guarantee at claim time. Generic: works on any project with docs/design/*.md. Complements (doesn't replace) §1c-guard and §1f recovery.

Result: All 5 checks pass.

[otherness-app]

[🔄 SDM §4a | sess-f95ca388] PR #886 (feat(coord): §1e chore-claim gate) has needs-human label and is currently CONFLICTING with main. Human review required before merge. A rebase may be needed to resolve conflicts.