fw(nav): drop the forced-poshold RC-alt-adjust guard - measured a bit-identical no-op

The guard blocked adjustFixedWingAltitudeFromRCInput during forced
poshold, defending against a real structural feedback (the nav loiter
writes rcCommand, this function reads rcCommand[PITCH] as a pilot climb
command). A/B on the floor-orbit flight was bit-identical with and
without it: the observed orbit climb was the missing-pitot centrifugal
compensation, fixed separately. Unproven defensive code is not worth
its upstream diff; the feedback class stays documented here.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: swissembedded

src/main/navigation/navigation_fixedwing.c

@@ -111,20 +111,6 @@ void resetFixedWingAltitudeController(void)
 
 bool adjustFixedWingAltitudeFromRCInput(void)
 {
-#if defined(USE_FW_AEROBATICS) || defined(USE_SOARING)
-    // Forced poshold (floor orbit / thermal loiter): NO RC altitude adjust.
-    // The nav loiter WRITES rcCommand to fly the circle, and this adjust
-    // reads rcCommand[PITCH] - the loiter's own pitch output fed back as a
-    // "pilot climb command" is a positive feedback loop that rode the
-    // floor orbit away from its anchor with the sticks untouched
-    // (measured: smooth pitch 8->23 deg, ~+4 m/s, 60 m past the anchor
-    // Z while nav actual == estimator Z). The anchor Z is the contract;
-    // pilot pitch is a TAKEOVER there, not a climb knob - same raw-stick
-    // lesson as the floor's release detection.
-    if (posControl.flags.forcedPosholdActive) {
-        return false;
-    }
-#endif
     int16_t rcAdjustment = applyDeadbandRescaled(rcCommand[PITCH], rcControlsConfig()->alt_hold_deadband, -500, 500);
 
     if (rcAdjustment) {