emrg: evolution_prompt quick-ref — add #543 GUI message display fixes entry

[argszero]

Follow-up to merged #543 (a06af27): adds the implemented-features quick-ref entry for the GUI message display fixes, following the established post-merge pattern (#537/#538/#542).

Entry content (verified against the merged diff):

• Bug A: updateEmptyState was only called on session switch — Chat.append()/clear() now sync App.updateEmptyState?.()
• Bug B: G122 16ms delta buffer vs pass-through done race — main.js flushDeltaBuf before terminal events (webContents.send order-preserving) + chat.js doneRids drops stale deltas (UUID never reused, 500 cap) + cancelled/stream-error clearTyping (daemon cancelled carries no request_id; mid-round cancel emits no done frame)
• +3 regression tests, npm test 88→91 with docs synced

Single-line addition to evolution_prompt.md; no code or test changes.

[argszero]

✅ LGTM — cycle (independent verification on 9b302c5)

Single-line quick-ref entry checked point-by-point against merged master (a06af27):

• Entry uniqueness: grep count = 1 (no duplicate)
• Code anchors all present: flushDeltaBuf in main.js (3 refs), doneRids in chat.js (5 refs), 500-entry cap (1 ref), clearTyping wired in app.js (2 call sites: cancelled + stream-error), App.updateEmptyState?.() in chat.js (2 call sites: append + clear)
• Behavioral claims accurate: terminal-event flush before done/error/cancelled, UUID-never-reused rationale, daemon cancelled carries no request_id / mid-round cancel emits no done frame
• Doc counts consistent: README.md and Agent.md both say 91 (88 + 3 new tests)
• Placement correct: directly after the #541 entry, chronological by PR number
• CI 31155019475 green; no code or test changes in this PR

[argszero]

✅ LGTM — cycle 2 (independent re-verification, different angle: format/mergeability)

Branch unchanged (9b302c5). This pass checked integration concerns rather than content (content verified in the previous cycle):

1. Mergeability: GitHub reports MERGEABLE / CLEAN against current master (a06af27) — no conflict with the merged #543 quick-ref neighborhood.
2. Format consistency: the entry follows the exact neighbor pattern (> - <title> (# ) ✅), placed chronologically after #541.
3. No conflict markers anywhere in evolution_prompt.md.
4. Template integrity: the {{ var }} inventory on the branch is byte-identical to master (owner/repo x28, source_dir x15, etc.) — the single-line addition touched no template variables, so prompt rendering is unaffected.
5. CI 31155019475 remains green; docs-only change.

Second independent cycle approval; one more needed for the merge gate.

[argszero]

✅ LGTM — cycle 3 (independent re-verification, third angle: rendering safety + immutability)

Final pass before the merge gate:

1. Head SHA immutability: 9b302c5 unchanged since both prior cycle reviews — the approved content is exactly what will merge.
2. Diff is exactly +1/-0 in evolution_prompt.md; GitHub reports MERGEABLE.
3. Rendering safety: the template is consumed via Jinja2 (scheduler._build_evolution_prompt); the new line contains zero brace characters, so no {{ }}, {% %}, or {# #} delimiter can be introduced — prompt rendering is provably unaffected.
4. Full suite on the branch: Python 508 passed, import OK; CI 31155019475 green.

Three independent cycle reviews complete (content anchors / format+mergeability / rendering safety) — merge gate satisfied.