Bound secret dialogs and preserve the full CLI save window after late input.
Keep provider configuration polling connected when Plasma delivers cached
data synchronously. Complete fallback slots once after parsing and report
account normalization failures for the affected provider.

Add regression tests that execute production prompt commands with synthetic
processes and exercise cached watcher replies. Both regressions were
reproduced on the previous PR head before validating the fixes.

Validation: make check passed locally with documented KDE-related skips.
CI passed on 2e3ecd44ea1a56459de74d1ee90ae272c52e772c, including all 74
Python tests, QML tests with zero skips, package and AppStream validation,
popup/panel smoke tests, PR title, and CodeQL.

Documentation impact: update CHANGELOG Unreleased, provider setup guidance,
and development test descriptions. README, TODO, configuration keys,
translations, metadata, and packaging requirements remain unchanged.