Warning screen
- New reusable WarningPage (word-wrapped message, ENTER acknowledges and
continues to the screen you were about to enter).
- First use: pressing Play while the selected audio is still downloading.
Dynamic Audio requires every file; a fixed track requires its own file.
License re-validation
- No longer re-verifies on every Home render. Checks now run only when the
email/license key is entered or changed, on the manual option, at startup
when already due, and hourly while valid.
- Invalid + unchanged credentials are never re-checked (persisted pair).
- Valid re-checks at most once per hour, anchored on a DB timestamp so an
overdue check runs immediately after a power cycle.
- New system_kv keys track the checked pair, outcome, and last-check time.
- Added a System Settings row "Manually Validate License Key OK|Invalid"
(OK green, Invalid red, label white) that runs a check immediately.
Portal / local integration
- License validation request now sends the app version as `appVersion`.
- The entered license key is mirrored to ~/.local/radiantwave/license.txt.
Misc
- "Please connect to WiFi" only shows when no WiFi is joined AND the internet
is unreachable (fixes the NetworkManager-missing and Ethernet cases).
- Added unit tests for the audio-download warning, license scheduling policy,
license request shape, and the new settings-menu entry.