Phase 3 (batch 6): route FM squelch + CTCSS through controller commands

The user plans to expose FM over web/CAT later, so FM controls get the
same controller treatment now — future web/CAT FM commands plug straight
into these.

- Relocate CTCSS_COUNT/CTCSS_TONES from MainForm to FMRepeater (a shared
  FM unit MainForm already uses) so TRadioController can drive CTCSS on the
  DSP. CTCSS_NAMES stays in MainForm (UI dropdown labels). MODE_FM is
  already visible to the controller via WDSPEngine.
- SetFMSquelch/SetFMSquelchLevel apply FM squelch (mode-gated) to the DSP;
  SetFMCTCSS/SetFMCTCSSTone clamp and apply CTCSS. All fire OnStateChanged.
- OnControllerState restyles the SQ/CTCSS buttons, syncs the squelch slider
  + label, and the CTCSS tone dropdown. Handlers/SetFMCTCSSTone call the
  commands (manual CTCSS still clears the auto-active flag in the handler).

FM repeater stays for the heavy batch — it needs XvtrTranslate/
ActiveTXFreqHz moved into the controller. ApplyFMSquelch remains for
band/mode re-apply paths (RestoreBand, XVTR).

Builds clean (cocoa).

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

FMRepeater.pas

@@ -22,6 +22,16 @@ const
   RPT_AUTO_MINUS_LO = 145600000.0;  // 145.600 MHz
   RPT_AUTO_MINUS_HI = 145787500.0;  // 145.7875 MHz
 
+  // CTCSS tones (38 standard tones). Здесь (а не в MainForm), чтобы таблица
+  // была доступна TRadioController для FDSPEngine.SetTXCTCSS. Имена тонов
+  // (CTCSS_NAMES) остаются в MainForm — это UI-метки выпадающего списка.
+  CTCSS_COUNT = 38;
+  CTCSS_TONES: array[0..CTCSS_COUNT-1] of Double = (
+    67.0,  71.9,  74.4,  77.0,  79.7,  82.5,  85.4,  88.5,  91.5,  94.8,
+    97.4,  100.0, 103.5, 107.2, 110.9, 114.8, 118.8, 123.0, 127.3, 131.8,
+    136.5, 141.3, 146.2, 151.4, 156.7, 162.2, 167.9, 173.8, 179.9, 186.2,
+    192.8, 203.5, 210.7, 218.1, 225.7, 233.6, 241.8, 250.3);
+
 { Returns default offset (Hz) for the given visible frequency.
   70 cm band → 7.600 MHz; everything else → 0.600 MHz. }
 function RptDefaultOffsetHz(FreqHz: Double): Double;