emrg: bump version to v0.2.81 (first release after React migration)

[argszero]

Release v0.2.81 — first release after the full GUI renderer React migration (host authorized 2026-08-27 09:38).

Version bump only (8 files, no code changes): emrg/init.py, emrg/gui/package.json + package-lock.json, packaging/build-runtime.sh, packaging/make-installer.sh, packaging/make-run-installer.sh, pyproject.toml, uv.lock.

Ships 37 commits since v0.2.80 (823cc81), including:

• GUI renderer React migration batches emrg: gui renderer React migration Batch 0 — infra scaffold (Vite 8 + React 19 + TS strict + Vitest + SnapshotStore) #991-emrg: gui renderer — settings: add custom task-type (template) management tab #1026 (Vite 8 + React 19 + TS strict + Vitest + SnapshotStore; daemon event bridge with sid routing; settings panel; final switch to renderer/dist; vanilla renderer deleted)
• emrg: gui renderer — wire workspace panels to real daemon data (projects/tasks/rants + project sessions) #1028 workspace panels wired to real daemon data (projects/tasks/rants)
• emrg: usage anchor — detect silent provider/tokenizer drift (issue #1027) #1029 usage-anchor silent provider/tokenizer drift detection (issue usage anchor lacks provider identity: silent drift when provider changes under an unchanged base_url #1027)
• emrg: add measured reader-feedback -> merged-fix latency metric (issue #1027) #1030 reader-feedback → merged-fix latency metric (issue usage anchor lacks provider identity: silent drift when provider changes under an unchanged base_url #1027)
• emrg: fix flaky DialogHost rename prefill assertion (waitFor useEffect-filled input) #1031 DialogHost rename prefill flake fix

Verified: pytest 1120 passed + 1 skipped (1121), renderer vitest 426/426, import + CLI report 0.2.81.

[argszero]

✅ LGTM 1/3 — cycle 2026-08-27T09:46:30. Version-only bump (8 files, +9/-9, no code changes): emrg/init.py, gui package.json + package-lock.json, 3 packaging scripts, pyproject.toml, uv.lock. Verified: import reports 0.2.81, CLI OK, pytest 1120 passed + 1 skipped, renderer vitest 426/426. Release body enumerates the 37 commits since v0.2.80 (React migration #991-#1026 + #1028/#1029/#1030/#1031).

[argszero]

✅ LGTM 2/3 — cycle 2026-08-27T09:56:27. Independent re-verification: head unchanged, CI 33031328854 green (test + test-windows), MERGEABLE/CLEAN. Version-only bump verified (8 files, import reports 0.2.81, pytest 1120+1, vitest 426/426). No new feedback since 1/3 (094630).

[argszero]

✅ LGTM 3/3 — cycle 2026-08-27T10:07:33. Independent re-verification: head unchanged (942ffd4), CI run 33031328854 green (test + test-windows), MERGEABLE/CLEAN. Version-only bump confirmed (8 files, import reports 0.2.81). No new feedback since 2/3 (095627). Merging and executing the v0.2.81 release.