Move public search scope into the Documents picker

[Paul Lizer (paullizer)]

Summary

• Move All/Visible public-search scope out of the permanent row above chat and into Documents → Search in, where users choose documents and retrieval context.
• Keep Documents under Manual controls in Orchestrate and preserve aggregate public retrieval, the directory handoff, and scope persistence across follow-up questions.
• Keep normal search behavior intact; add picker recovery guidance, opt-in scope control wiring, regression coverage, and updated documentation.

Linked issue

Refs #1722 (aggregate public chat row; this PR covers scope-control placement only)

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

Testing / validation

• npm --prefix .\application\v2_ui run build - passed (existing bundle-size warning remains).
• python -m pytest .\functional_tests\test_v2_chat_context_picker.py .\functional_tests\test_v2_public_chat_scope.py -q --disable-warnings - 38 passed.
• python -m pytest .\ui_tests\test_v2_public_chat_scope.py .\ui_tests\test_v2_public_directory.py .\ui_tests\test_v2_chat_context_selection.py -q - 125 passed.
• python .\ui_tests\test_v2_orchestration_composer.py - 7 checks passed.
• python .\functional_tests\test_docs_app_surface_coverage.py - 7 checks passed; python .\functional_tests\test_docs_site_quality.py - 6 checks passed.
• node "C:\Users\paullizer\AppData\Roaming\com.github.githubapp\app-skills\impeccable\scripts\detect.mjs" --json .\application\v2_ui\src\components\chat\Composer.tsx .\application\v2_ui\src\components\chat\ComposerEditor.tsx .\application\v2_ui\src\components\chat\DocumentPickerPopover.tsx - no deterministic findings. Reviewed local Chromium screenshots at 1440px and 390px in light/dark themes with long configured workspace labels; the production Azure app was not changed or tested.
• git -c core.whitespace=blank-at-eol,blank-at-eof,space-before-tab,cr-at-eol diff --check - passed.

Documentation

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

Release notes were left unchanged; this interaction cleanup does not introduce a separately advertised feature.

Security checklist

• New Flask routes include @swagger_route(security=get_auth_security()) (no Flask routes added)
• Settings sent to non-admin frontends use sanitize_settings_for_user() (no settings payloads added)
• 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