feat(addie): lead with coverage before drafting RFC issues

[bokelley]

Summary

• Extends Addie's "Spec Feedback Response Pattern" in server/src/addie/rules/behaviors.md with two clauses inside the existing 1-VERIFY / 2-POSITION / 3-CLOSE-LOOP structure.
• Step 2 gains "Lead with coverage when verification reveals overlap": if search_docs / get_schema show overlap with existing primitives, the reply must open with what's already covered before anything else. Factually wrong premises (proposal extends a non-existent field) get a one-line correction first.
• Step 3 gains "Draft only after the caller has seen the coverage statement": when step 2 surfaces overlap or factual error, draft_github_issue is NOT called in the same turn as verification. Coverage-leading reply first, draft on confirmation.

Why

Same-Addie-different-answers failure on 2026-05-01: Jeffrey Mayer (DanAds) drafted four RFCs with web-Addie, posted to Slack, Slack-Addie pushed back on each with spec citations. Both surfaces use the same rules — the rule itself was missing the load-bearing instruction. The existing rule listed "does the spec already handle this?" as one of four bullets to consider; it didn't say "if yes, lead with that before drafting."

Validation

Eval at #3804 with RFC_USE_LOCAL_PROMPT=1 (validates against this branch's rules, not deployed prod) at N=3 runs per scenario:

Scenario	Without rule (prod prompt)	With rule (this branch)
CPQ pricing	0/3 — drafted on every run	3/3 — no draft
TMP signals cap	varies — sometimes drafts	3/3 — no draft
Bilateral trust	varies	3/3 — no draft
brand.json	varies	3/3 — no draft
Total	inconsistent	12/12 runs, 0 premature drafts

Under the rule, draft_github_issue does not fire in the same turn as the verification on any of the 12 runs. The model leads with "most of this is already covered: pricing_options + buying_mode: refine + account" and offers to draft a narrower scope on confirmation — exactly the Slack-Addie behavior from Jeffrey's screenshot.

Dependencies

Should land after #3804 (eval framework). The eval is the regression check that this rule edit holds up over time.

Files

• server/src/addie/rules/behaviors.md — the rule edit
• .changeset/addie-spec-feedback-coverage-rule.md — empty changeset (non-protocol change)
• static/schemas/source/index.json — pre-existing main-branch hygiene fix the pre-push hook required (one-line "published_version": "3.0.3" added by npm run build:schemas)

Test plan

• CI green
• Manual smoke: eval at RFC_USE_LOCAL_PROMPT=1 shows 3/3 on CPQ at N=3
• After deploy, the same eval at default (prod prompt) should also show 3/3 on CPQ — confirms the rule is live