fix: make beacons session-only, slower and QSY-aware (#171)

Forgotten beacons kept filling the chat while nobody was at the station.

- The two enable switches are session state now: they start off, are
  never read from preferences.xml and are always stored as "false", so
  neither a stored switch nor an older release reading a newer file can
  start a beacon. The in-code default was "on" and started a beacon
  whenever the file was unreadable or had no <beaconCQ> block.
- The minimum interval rises from 1 to 5 minutes; the bundled template
  ships 10 instead of 1. Smaller stored values are raised when the
  timer is scheduled.
- BeaconFrequencyGuard switches a beacon off once a logger-reported
  transceiver frequency lies more than 2 kHz from the one reported when
  the beacon was switched on. UCXLog RadioInfo and Win-Test STATUS feed
  it wherever they already set MYQRG/SECONDQRG. Without SO2R the single
  radio stands for both categories, with SO2R each radio for its own.

Manual (DE/EN), changelog, website and PROJECT_CONTEXT updated.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NJ1tUJVmWChD9V5Pg7uH8X

docs/superpowers/specs/2026-11-04-live-beacon-control-design.md

@@ -2,6 +2,12 @@
 
 Freigegeben von Marc am 2026-11-04.
 
+> **Teilweise abgelöst durch Issue #171 (2026-11-11):** Die Beacon-Zustände werden nicht mehr
+> gespeichert und nicht mehr beim Profilstart geladen; jede Sitzung beginnt mit „aus“. Das
+> Mindestintervall beträgt fünf Minuten, und eine TRX-Frequenzänderung über 2 kHz schaltet die
+> Beacon ab. Der aktuelle Stand steht in `docs/PROJECT_CONTEXT.md` unter „Autoanswer / Beacon“.
+> Alles Übrige in diesem Dokument gilt weiter.
+
 ## Ziel
 
 Die beiden Beacon-Aktivierungsschalter wirken in der laufenden Sitzung sofort. Der gemeinsame