fix(radiolib): keep LR1121 tx power valid across sub-GHz and 2.4 GHz

- Clip requested power to the active PA's range instead of failing. A
  stored 22 dBm was rejected at 2.4 GHz (HF PA max 13 dBm), and since
  setTxPower ignores errors the sub-GHz PA stayed configured.
- Re-apply the requested power after every successful retune: PA choice
  depends on the band, and set radio / tempradio only call setParams.

src/helpers/radiolib/CustomLR1121.h

@@ -9,6 +9,8 @@ class CustomLR1121 : public LR1121 {
   uint32_t _activityAt = 0;
   bool _headerSeen = false;
   bool _rx_boosted = false;
+  int8_t _txPower = 0;
+  bool _txPowerSet = false;
 
   public:
     CustomLR1121(Module *mod) : LR1121(mod) { }
@@ -36,12 +38,32 @@ class CustomLR1121 : public LR1121 {
       return len;
     }
     
-#ifdef LR1121_FORCE_HP_PA
-    // boards with only RFO_HP_LF wired: stop RadioLib switching to the LP PA at <= 14 dBm (2.4 GHz still uses the HF PA)
+    using LR1121::setOutputPower;
+    using LR1121::setFrequency;
+
     int16_t setOutputPower(int8_t power) override {
-      return LR1121::setOutputPower(power, true);
-    }
+#ifdef LR1121_FORCE_HP_PA
+      const bool force_hp = true;   // boards with only RFO_HP_LF wired: never select the LP PA
+#else
+      const bool force_hp = false;
 #endif
+      // clip to the active PA's range (HF PA tops out at 13 dBm) rather than fail and keep the other band's PA
+      int8_t clipped = power;
+      checkOutputPower(power, &clipped, force_hp);
+      int16_t state = LR1121::setOutputPower(clipped, force_hp);
+      if (state == RADIOLIB_ERR_NONE) {
+        _txPower = power;
+        _txPowerSet = true;
+      }
+      return state;
+    }
+
+    int16_t setFrequency(float freq) override {
+      int16_t state = LR1121::setFrequency(freq);
+      // PA selection depends on the band, and set radio / tempradio don't call setTxPower
+      if (state == RADIOLIB_ERR_NONE && _txPowerSet) state = setOutputPower(_txPower);
+      return state;
+    }
 
     float getFreqMHz() const { return freqMHz; }