emrg: document fork-PR conflict CI unblock path in evolution prompt (#716 lesson)

[argszero]

Operational lesson from reviewing PR #716 this cycle: a conflicting fork PR gets zero CI checks (mergeable: CONFLICTING / mergeable_state: dirty) — GitHub refuses to run CI for a dirty PR, close/reopen does not re-fire checks, and gh workflow run cannot target fork refs. The unblock path is a maintainer push to the fork branch (maintainer_can_modify: true): fetch refs/pull/N/head, merge master locally, resolve the conflict, push to the fork branch → the pull_request synchronize event fires CI.

Adds this to the review guidance in emrg/server/evolution_prompt.md (2 lines, doc-only) plus a quick-ref entry, so future cycles resolve dirty fork PRs directly instead of spending cycles on re-trigger attempts.

• pytest 747 green, doc-count 3/3, import + CLI green

[argszero]

✅ LGTM — cycle (1st)

Doc-only change (2 insertions to evolution_prompt.md): review guidance now covers the distinct scenario where a conflicting fork PR gets zero CI checks and workflow_dispatch cannot reach fork refs — with the maintainer-push unblock path that worked for #716. Local: pytest 747, doc-count 3/3, import + CLI green. CI run 31593247824 PASS.

[argszero]

✅ LGTM — cycle

Verified on head 091bb20 (base 0b03e41, 1 file +2/-0, doc-only):

1. Accuracy — both edits are faithful to the #716 incident: a CONFLICTING fork PR gets zero CI checks (mergeable_state dirty → GitHub refuses to run CI; close/reopen does NOT re-fire; gh workflow run cannot target fork refs), and the working unblock is a maintainer push to the fork branch (maintainer_can_modify → fetch refs/pull/N/head → merge master locally → resolve → push → synchronize event fires CI). Matches what actually unblocked #716 this cycle (commit 1b50d5e).
2. Placement — lands under the existing #644 CI-check pre-LGTM guidance in Step 1.1, plus a quick-ref entry. No overlap/duplication with the #527/#529 retrigger instructions (those handle non-fork pushes; this covers the fork-conflict case).
3. Doc-only — evolution_prompt.md is not part of the doc-count guard; import + CLI green, doc-count 3/3, CI Test 31593247824 PASS.

No issues.

[argszero]

✅ LGTM — cycle (3rd)

Doc-only evolution_prompt.md review-guidance addition (fork-PR conflict → zero CI checks → maintainer-push unblock path, #716 lesson). Head 091bb20 unchanged; CI run 31593247824 PASS; master-side verification unaffected (pytest 748 on current master). Merge-ready.