fix(flomni): check OSA collision warning against fosaz's defined IN position

The foptz-target OSA-collision warning was checking fosaz's current live
readback, but fosaz is normally parked safely OUT except when actually in
use -- so the warning would almost never fire in practice. Check against
fosaz's "in" user_parameter instead (the same nominal position
FlomniOpticsMixin.fosa_in() itself checks before refusing a fosaz move),
since that's the real question: would this foptz target collide with the
OSA if it were swapped in.

Live-verified against the running simulated flomni session: fosaz's
defined IN position is 13.1mm; the warning now correctly engages right at
the real physical crossover (foptz=19 -> +0.90mm clearance, safe;
foptz=20 -> -0.10mm, warns), matching compute_osa_remaining_space()
exactly through the real dialog/client/device-RPC code path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NPZ9gzN2rt3wgiMnTKyrug

csaxs_bec/bec_widgets/widgets/tomo_params/tomo_params.py

@@ -2193,12 +2193,19 @@ class CommandJobBuilderDialog(QDialog):
         """Live, advisory-only OSA-collision warning for
         move_foptz_with_shift's foptz_target field.
 
+        Checked against fosaz's *defined* IN position (its "in"
+        user_parameter), not wherever fosaz happens to be reading right
+        now -- fosaz is normally parked safely OUT except when actually in
+        use, so checking the live position would almost never warn. The
+        real question is "if the OSA were swapped in at its nominal
+        position while foptz is at this target, would it collide", which
+        is also exactly what FlomniOpticsMixin.fosa_in() itself checks
+        (and refuses on) for fosaz moves -- this surfaces the same check
+        here, at data-entry time, for foptz instead.
+
         The move itself stays a plain absolute move (see
-        _queue_action_move_foptz_with_shift's docstring) -- this just
-        surfaces, at data-entry time, the same clearance check
-        FlomniOpticsMixin.fosa_in() enforces (by refusing) for fosaz moves,
-        so an operator can see a likely OSA collision before queuing a
-        foptz target, without the queue action itself blocking on it.
+        _queue_action_move_foptz_with_shift's docstring) -- this is
+        advisory only, the queue action itself doesn't block on it.
         """
         from csaxs_bec.bec_ipython_client.plugins.flomni.flomni_optics_mixin import (
             compute_osa_remaining_space,
@@ -2217,14 +2224,17 @@ class CommandJobBuilderDialog(QDialog):
             if fosaz is None:
                 return
             try:
-                fosaz_val = fosaz.readback.get()
+                fosaz_in = (fosaz.user_parameter or {}).get("in")
             except Exception:
                 return
-            clearance = compute_osa_remaining_space(foptz_widget.value(), fosaz_val)
+            if fosaz_in is None:
+                return
+            clearance = compute_osa_remaining_space(foptz_widget.value(), fosaz_in)
             if clearance <= 0:
                 lbl.setText(
-                    f"Warning: at this foptz target, OSA clearance would be "
-                    f"{clearance:.2f} mm (<=0 = collision risk with a normal OMNY pin)."
+                    f"Warning: at this foptz target, OSA clearance at its defined "
+                    f"IN position ({fosaz_in:.2f} mm) would be {clearance:.2f} mm "
+                    "(<=0 = collision risk with a normal OMNY pin)."
                 )
                 lbl.setVisible(True)
             else: