fix(rig): saturated encoder flicks slam to the end stop

rel_delta caps one message at +-63 (7-bit offset-64); firmware acceleration
compresses a fast flick to 1-2 messages, so flick-to-max landed at ~125.
A saturated delta in the end-stop band (>=115 up / <=12 down) now snaps to
127/0 — slow turns never saturate, precise control untouched. Feel bands,
PLN vetoes at rehearsal.

tools/lcxl3-driver.py

@@ -1704,6 +1704,24 @@ class Driver:
                         value = self.tempo_step(self.values.get(v2, 0), d)
                     else:
                         value = max(0, min(127, self.values.get(v2, 0) + d))
+                        # End-stop slam for flicks. Measured 2026-09-22: the
+                        # wire carries a 7-bit delta (rel_delta = v - 64), so
+                        # one message tops out at +-63, and the firmware's
+                        # acceleration compresses a full-speed flick into 1-2
+                        # messages — a flick to max lands at ~125 instead of
+                        # 127. If the delta is SATURATED (the wire's maximum:
+                        # >= 63 up, <= -63 down) and the post-integration
+                        # value is already in the top band (>= 115) or bottom
+                        # band (<= 12), treat intent as "reach the stop" and
+                        # snap there. Slow precise turns (+-1/+-2) never have
+                        # a saturated delta, so they are untouched. The bands
+                        # are a FEEL decision — PLN can veto/retune them at
+                        # rehearsal. Tempo keeps its detent path (tempo_step
+                        # above); the slam only lives in this plain else.
+                        if d >= 63 and value >= 115:
+                            value = 127
+                        elif d <= -63 and value <= 12:
+                            value = 0
                     if self.lang:
                         if value == self.values.get(v2):
                             continue               # pinned at an end stop