feat: QO-100 beacon lock — robustness, persistence, FT8-aware UI

Builds on the beacon-lock baseline: keeps the proven display-FFT control
path (hardware-LO trim folded into the active transverter LOError), and
hardens it. The narrowband NCO/FLL scaffold (BeaconLock.pas) is removed —
it was never in the control path.

- RadioController:
  * Persist live: each correction folds straight into the active xvtr
    LOError (visible in Settings, survives restart as LNB calibration);
    disk writes throttled. FBeaconLockHz is now only a session indicator.
  * Robust tracking vs nearby signals: narrow ±2 kHz gate while locked
    (±6 kHz only for acquisition), slew-rate outlier rejection (a sudden
    centroid jump = interferer, not slow LNB drift → ignored), and lobe
    shape validation in MeasureBeaconFFT (width + power symmetry) so a CW
    carrier / one-sided neighbour isn't mistaken for the BPSK beacon.
    Prominence measured over the in-window noise floor (gate-width robust).
  * Fast convergence: feed-forward (predict post-retune position so the
    window follows the beacon through the jump) + near-deadbeat correction
    on the manual click → one click locks instead of repeated tapping.
  * Single central BPSK beacon (10489.750); dead CoarseBeaconOffset and
    unused throttle counters removed; stale NCO/FLL/4 Hz comments fixed.
- WDSPEngine: drop the per-sample TBeaconTracker RX-IQ tap (tracker gone).
- MainForm: BEACON is now a plain button, shown only on Pluto in a
  transverter. Lock status (off / click / search / LOCK + correction +
  prominence) moves to status-bar field 7 in place of PLL on Pluto;
  openHPSDR keeps PLL there.
- SettingsForm/StatusBar: widen LO Error field to ±10 MHz (QO-100 LNBs
  drift hundreds of kHz) and widen status field 7 for the beacon text.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

StatusBar.pas

@@ -33,7 +33,8 @@ const
   PAD_X    = 8;
   SEQ_MIN_W = 90;
   STATUS_ORDER: array[0..7] of Integer = (2, 0, 1, 3, 7, 4, 5, 6);
-  BASE_W: array[0..7] of Integer = (280, 160, 170, 150, 190, 180, 130, 90);
+  // поле 7: PLL (openHPSDR) ИЛИ статус QO-100 beacon lock (Pluto) — шире под "BCN LOCK …".
+  BASE_W: array[0..7] of Integer = (280, 160, 170, 150, 190, 180, 130, 200);
   INITIAL_TEXT: array[0..7] of string = (
     'Board --',
     'IP --',