Apply structural I12 gate to the process-newsletter WATCH path?

Why this has to be structural

The I12 invariant requires curation/hybrid vault notes to contain exactly one of:

• ## Curation section
• ## Issue contents

The subagent, under instruction load, substitutes a semantically plausible synonym. The space of plausible synonyms is unbounded — no wording enumeration can close it. The /improve recurrence guardrail (added 2026-06-29) now explicitly disallows a third wording fix for the same pattern.

The proposed fix adds a new Step 3b to the Mode 4 watch orchestrator loop in process-newsletter/SKILL.md: after each subagent writes its note, the parent (which has no instruction-load synonym risk) checks I12 inline — reads the file, checks newsletter_format, verifies the heading. If it fails, the parent re-dispatches a targeted single-turn correction: rename the heading, nothing else. Cap: 1 re-dispatch per note; failures after retry surface as I12-FAIL in the run report.

What changes in SKILL.md

A new Step 3b block inserted between Step 3 (subagent spawn) and Step 4 (parent collects summaries) in Mode 4. The parent gate is:

• Read the written file, check newsletter_format frontmatter
• If curation or hybrid: verify body contains ## Curation section or ## Issue contents (case-insensitive level-2 heading)
• Pass: collect summary, continue
• Fail: re-dispatch with exact correction prompt; log I12-FAIL if still failing after 1 retry

No other Mode 4 steps change. The subagent prompt and pre-write checklist stay unchanged.

Acceptance criterion

Over a 2-week observation window (2 Review cycles), every fresh curation/hybrid note passes audit-newsletter-outputs.py --strict I12 on first write or after the one automatic re-dispatch — with zero /self-review --fix I12 repairs needed.

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