v0.27.0 - Custom Night blend duration and preserved recording reports

Night camera now offers a Custom blend duration, from 1 to 30 seconds in exact milliseconds. For example, choose 1.5 or 15 seconds while retaining automatic brightness. Auto remains the default, and manual durations exceeding Capture every stay visible with a correction prompt before recording. This sets a requested software blending window; it does not control the camera shutter or guarantee camera timing.

Refreshing sources now preserves the last recording outcome, including the recovery path after a finalization failure. Temporary preview errors can still be cleared by retrying, and starting a new recording replaces the old outcome.

Validation: warning-free Release build and all 57 synthetic suites, plus an independent source-archive rebuild with nine focused suites. Checks cover custom input, saved preferences, cancellation, keyboard/high-DPI layout, and recording-report retention using generated video. Installer/portable/source metadata, manifests and checksums were verified. No physical camera or desktop capture was used.