SIA v1.7.3 — continuity explains itself

Continuity now explains its automatic protection directly in the cockpit.

• Shows whether the authenticated automatic schedule is on.
• Shows hourly and weekly last/next timer starts.
• Makes clear that hourly backup needs no button press.
• Explains no-wake sleep behavior and persistent catch-up.
• Renames the manual action to an optional extra copy with immediate deep verification.
• Authenticates both timers and both target services before making a green automatic-backup claim.
• Adds the read-only sia backup schedule interface and explicit WakeSystem=false policy.

Verified by the complete 876-test suite, live v1.7.3 installation, exact loaded-release attestation, and visual inspection of both Continuity surfaces.