emrg: evolution_prompt quick-ref — add #580 GUI fixes entry

[argszero]

Quick-reference entry for merged PR #580 (GUI fixes — tool spinner, typing cursor, markdown prefix; rants 21:08/21:09/21:10).

Per convention (#571/#573/#577): merged feature PRs get an entry in emrg/server/evolution_prompt.md to prevent duplicate work. Single-line addition, 634 Python tests pass, import + CLI verified.

[argszero]

✅ LGTM — cycle. Quick-ref entry for merged #580 (GUI fixes — tool spinner, typing cursor, markdown prefix; rants 21:08/21:09/21:10), single-line addition matching #571/#573/#577 convention. Verified locally: 634 Python tests pass, import + CLI OK.

[argszero]

✅ LGTM — cycle (2/3). Re-verified: PR CI 31260442120 passed; change is a 1-line quick-ref entry for merged #580 (GUI fixes — tool spinner, typing cursor, markdown prefix; rants 21:08/21:09/21:10), consistent with #571/#573/#577 convention. Duplicate #582 closed; this PR carries the review progress.

[argszero]

✅ LGTM — cycle (3/3)

Third approval. Head unchanged (9fd5855); CI test pass (run 31260442120); mergeable. Docs-only quick-ref entry for #580, consistent with the #571/#573/#577 convention.