Move repeat scheduling to the message action bar

[Paul Lizer (paullizer)]

Summary

• Remove the permanently visible "Repeat on a schedule" button from completed AI answers. Offer scheduling as a calendar icon alongside Copy and Retry in the existing hover/keyboard-focus message action bar.
• Clicking the calendar expands the existing scheduling form below the answer. Collapse restores focus to the icon; masking or changing the run closes the panel without reusing another run's preview.
• Preserve feature switches, private-conversation eligibility, workflow exclusions, preview/save contracts, and scheduling defaults. Keep action groups usable on narrow screens and add focused regression coverage.

Linked issue

N/A. The user chose not to create an issue for this change.

Release Notes & Latest Features

• New Feature
• Bug Fix
• UI Enhancement
• Breaking Change
• Internal only

Is this visible to end users?

• Yes
• No

Is this admin-facing (Admin Settings, governance, deployment, config)?

• Yes
• No

Should this become a Latest Feature card?

• Yes
• No
• Already added

Screenshot needed for the card?

• Yes
• No
• Attached

Version bump

• application/single_app/config.py VERSION third segment bumped, or not needed because this is docs-only
• deployers/version.txt bumped, or not needed because deployers/ was not changed

Application version: 0.261.337 -> 0.261.338. No deployer changes.

Testing / validation

• npm --prefix .\application\v2_ui run build -- --outDir ..\..\ui_tests\artifacts\orchestration-plan-editor - passed, including TypeScript compilation. Vite reports its existing large-chunk warning.
• .\.venv\Scripts\python.exe -m pytest .\ui_tests\test_v2_workflow_plan_replay_card.py -q --tb=short - passed, 27 tests. Covers real components with production CSS, desktop/light and mobile/dark layouts, hover/keyboard reveal, placement, collapse/reopen, eligibility, stale-run/masking changes, errors, and existing save/refusal behavior.
• .\.venv\Scripts\python.exe -m pytest .\functional_tests\test_v2_message_actions.py -q -k 'not retry_and_edit_are_two_step_flows' --tb=short - passed, 7 tests; 1 existing test excluded as described below.
• node --test .\functional_tests\test_v2_workflow_plan_replay_client.mjs - passed, 9 tests.
• python .\scripts\build_docs_inventory.py - passed; generated inventory content is unchanged.
• python .\functional_tests\test_docs_app_surface_coverage.py - passed, 7 checks.
• python .\functional_tests\test_docs_site_quality.py - passed, 6 checks.
• git -c core.whitespace=blank-at-eol,blank-at-eof,space-before-tab,cr-at-eol diff --check - passed.
• Inspected desktop and mobile browser screenshots: the calendar sits beside Retry, and the expanded form is outside the answer bubble. Local-only test artifacts are not committed.

Known pre-existing test failure: test_retry_and_edit_are_two_step_flows expects the source literal 'chat_request': chat_request, but the existing route returns 'chat_request': body. The unchanged test from HEAD reproduced the same assertion failure. This PR leaves the unrelated assertion and production Retry behavior unchanged rather than treating the failure as a pass.

Documentation

• Release notes updated, or not needed
• Feature documentation updated, or not needed
• Fix documentation updated, or not needed

Updated the workflow plan replay feature documentation, chat-control reference, and workflow creation guide. Added docs/explanation/fixes/PLAN_REPLAY_MESSAGE_ACTION_FIX.md with behavior, version, coverage, and validation details. Release notes were not updated in this change.

Security checklist

• New Flask routes include @swagger_route(security=get_auth_security())
• Settings sent to non-admin frontends use sanitize_settings_for_user()
• Browser JavaScript is served from local SimpleChat static assets only; no CDN-hosted JS
• No secrets, keys, connection strings, or local-only artifacts are included

No Flask routes, authorization boundaries, or settings-response handling changed. The calendar uses the existing locally bundled Lucide icon. Existing replay eligibility and inert hostile-text browser coverage are retained.