Add rendered UI coverage for admin tabular run controls

[Paul Lizer (paullizer)]

Summary

• replace the Admin tabular controls template scan with a rendered, authenticated Playwright regression
• exercise real form interaction, POST-to-GET save redirect, explicit reload persistence, and verified restoration of every changed value
• guard shared settings mutation behind an isolated-environment opt-in and use only routable legacy direct/APIM deployments
• skip multi-endpoint environments because the configured chunk-model setting does not preserve endpoint context
• merge the latest Development, resolve the application version at 0.250.170, and add the issue to the release notes and fix documentation

Validation

• controlled rendered Playwright run: 1 passed
• post-test persistence state: all original values restored
• POST redirect contract: redirect accepted; direct POST 200 rejected
• legacy direct/APIM deployment discovery: passed
• python -m pytest ui_tests/test_admin_tabular_run_controls.py --collect-only -q: 1 test collected
• python -m pytest functional_tests/test_app_version_assertion_guardrails.py functional_tests/test_versioning_helper.py functional_tests/test_tabular_execution_settings_sanitization.py -q: 4 passed
• release-note and version alignment check: passed at 0.250.170
• targeted Python compilation and staged diff whitespace check: passed

The live repository-environment invocation skips when the authenticated UI URL, storage state, or explicit mutation opt-in is absent, as designed.

Baseline note

functional_tests/test_changed_files_action_version.py still fails on the base branch because it expects the literal tj-actions/changed-files@v46.0.1 reference while the workflow uses the SHA-pinned equivalent with a # v46.0.1 comment. This PR does not modify that unrelated workflow or test.

Fixes #1201