feat(ui): streamline chat actions and retire announcements

[GCWing]

Summary

Streamline transcript actions: combine edit and rollback in the user-message menu, move image export into the response copy menu, and offer illustrated export choices that omit or expand thinking. Exported messages retain their full text and reference presentation and use the transcript reading column with minimal branding.

Retire built-in announcements, startup tips, and the release-letter UI, including their scheduler, service feature, desktop commands, appearance entries, and generated capability projections. Retain the saved startup-tip preference for legacy configuration round trips. Align custom Checkbox fills and marks with the existing Switch theme tokens and system forced colors.

Type and Areas

Type: UI/UX, refactor, compatibility tests.

Areas: Web UI, design-system UI, desktop/Tauri, Rust assembly/services/contracts, capability catalog, developer scripts.

Motivation / Impact

Transcript actions use fewer visible controls while keeping disabled reasons, keyboard dismissal, focus restoration, and export progress/error feedback. Startup no longer loads or displays retired promotional content. Existing notification preferences remain readable and survive serialization.

Verification

Passed locally:

• pnpm run fmt:rs and git diff --check
• pnpm run check:web (includes Appearance, typography, theme color/visual contracts, and type checking)
• pnpm --dir src/web-ui run test:run src/flow_chat/components/modern/MessageExportControls.test.tsx src/flow_chat/components/modern/UserMessageItem.test.tsx src/flow_chat/components/modern/UserMessageItemActions.test.ts src/infrastructure/api/adapters/peer-device-adapter.test.ts src/infrastructure/appearance/runtime/AppearanceOverlayHost.test.ts src/infrastructure/appearance/registry/AppearanceRegistry.test.ts src/shared/ui/MenuComposition.contract.test.ts src/app/scenes/settings — 38 files, 295 tests
• cargo test --locked -p openbitfun-config-contracts --lib — 96 tests, including the legacy startup-tip preference round trip
• cargo test --locked -p openbitfun-product-domains --no-default-features --lib remote_surface — 19 tests
• pnpm run check:core-boundaries:test and pnpm run check:core-boundaries
• pnpm run capabilities:check and pnpm run capabilities:test
• pnpm run i18n:audit
• pnpm --dir design-system run build:ui
• node --test design-system/packages/ui/tests/checkbox.test.mjs
• node --test scripts/dev-startup.test.mjs

After synchronizing with the accepted-steering-message change on main, also passed:

• pnpm run type-check:web
• pnpm --dir src/web-ui run test:run src/flow_chat/components/modern/MessageExportControls.test.tsx src/flow_chat/components/modern/UserMessageItem.test.tsx src/flow_chat/components/modern/UserMessageItemActions.test.ts src/flow_chat/timeline/hostQueueProjection.test.ts src/flow_chat/timeline/useHostQueueTimeline.test.tsx — 5 files, 60 tests, including queued-message action gates

CI passed on commit 78fb2e7523e8f50e18da7450bb8e1872bae4f45d: all 14 checks succeeded, including three-platform Rust/CLI coverage, Linux x64/ARM64 binary and installer validation, Relay image validation, and the final Rust/CLI result. CI run.

Reviewer Notes

AI-assisted; testing level: focused automated checks. UI interaction and exported-image visual fidelity remain unverified; browser/computer-use verification was not requested.

Remote coverage: mocked Peer Device adapter behavior and compiled Product Operation Registry contracts only. Actual SSH remote workspace, relay/IM remote control, Peer Device connections, and Detached Dispatch were not exercised.

Announcement state files are left intact. The retired enable_startup_tips configuration field remains readable and writable for upgrade compatibility, with no runtime effect.

Checklist

• This PR contains the current UX and announcement-cleanup work without temporary artifacts or secrets.
• Relevant verification and its limits are recorded above.
• User-facing strings, docs, and locale resources are updated.