UI: collapse W axis to home-only (drop set-zero / W-origin)

The W axis homing already drives toward the configured limit (home_dir
in aux.json, default '-') and lands at home_position_mm = 0, so
'home' and 'zero' are the same point. Remove the now-redundant 'W
Origin' (move-to-zero) and 'Set W to 0' map-marker buttons; keep just
W-, W+, and a single Home W button. Also drop the unused
aux_move_zero / aux_set_zero JS handlers.

src/js/control-view.js

@@ -771,12 +771,6 @@ module.exports = {
       });
     },
 
-    aux_set_zero: function () {
-      api.put("aux/set-zero", { mm: 0 }).catch(function (err) {
-        console.error("W set-zero failed:", err);
-      });
-    },
-
     aux_jog: function (delta_mm) {
       api.put("aux/jog", { mm: delta_mm }).catch(function (err) {
         console.error("W jog failed:", err);
@@ -792,14 +786,6 @@ module.exports = {
       this.aux_jog(delta_mm);
     },
 
-    // "W Origin" - move W to 0 (absolute). Distinct from aux_set_zero,
-    // which sets the *current* position as the new zero without moving.
-    aux_move_zero: function () {
-      api.put("aux/move", { mm: 0 }).catch(function (err) {
-        console.error("W move-to-zero failed:", err);
-      });
-    },
-
     show_set_position: function (axis) {
       SvelteComponents.showDialog("SetAxisPosition", { axis });
     },

src/pug/templates/control-view.pug

@@ -108,7 +108,9 @@ script#control-view-template(type="text/x-template")
                   span {{jog_incr_amounts[display_units].large}}#[span.jog-units {{metric ? 'mm' : 'in'}}]
 
             // W axis jog row (auxcnc). Only shown when the aux controller
-            // is enabled in aux.json.
+            // is enabled in aux.json. We treat home == 0 for the W axis,
+            // so there is no separate "set zero" / "W origin" button -
+            // just W-, W+, and Home.
             tr(v-if="w.enabled")
               td(style="height:100px", align="center", colspan="1")
                 button(@click="aux_jog_incr(-1)",
@@ -117,12 +119,6 @@ script#control-view-template(type="text/x-template")
                   | W-
                   .fa.fa-arrow-down
 
-              td(style="height:100px", align="center", colspan="1")
-                button(@click="aux_move_zero()", :disabled="!w.enabled")
-                  | W
-                  br
-                  | Origin
-
               td(style="height:100px", align="center", colspan="1")
                 button(@click="aux_jog_incr(+1)",
                   :disabled="!w.enabled",
@@ -130,8 +126,9 @@ script#control-view-template(type="text/x-template")
                   | W+
                   .fa.fa-arrow-up
 
-              td(style="height:100px", align="center", colspan="1")
+              td(style="height:100px", align="center", colspan="2")
-                button(@click="aux_home()", :disabled="!w.enabled")
+                button(@click="aux_home()", :disabled="!w.enabled",
+                  style="height:100px;width:200px")
                   | Home
                   br
                   | W
@@ -235,15 +232,15 @@ script#control-view-template(type="text/x-template")
                 | {{w.tstate}}
 
               th.actions
-                // Invisible placeholder so the W marker/home buttons line
+                // Invisible placeholders so the W home button lines up
-                // up under the same columns as the X/Y/Z buttons above
+                // under the X/Y/Z home column. The W axis has no "set
-                // (which have a third "set position" cog).
+                // position" cog and no "zero offset" marker - home == 0.
                 button.pure-button(disabled,
                   style="height:60px;width:60px;visibility:hidden")
                   .fa.fa-cog
 
-                button.pure-button(title="Set W axis position to 0.",
+                button.pure-button(disabled,
-                  @click="aux_set_zero()", style="height:60px;width:60px")
+                  style="height:60px;width:60px;visibility:hidden")
                   .fa.fa-map-marker
 
                 button.pure-button(:disabled="!w.enabled", @click="aux_home()",