fix: make camera node strap loops vertical

hardware/case/camera-node-case-v4.scad

@@ -1,11 +1,11 @@
 // RemoteRig camera node case v4
 // Upright appliance-style OpenSCAD prototype for a strap-mounted camera node.
 // Units: millimeters. Coordinate system: X=width, Y=depth/front-back, Z=height.
-// Front/service lid is on the -Y face. Rear strap channels are on the +Y face.
+// Front/service lid is on the -Y face. Rear zip-tie pass-through loops are on the +Y face.
 //
 // v4 visual direction: tall/upright appliance/control box matching the original
 // reference image, replacing the rejected wide, low generic electronics box.
-// Nominal body: 56 W x 36 D x 82 H mm; with low rear strap bridges ~40 D.
+// Nominal body: 56 W x 36 D x 82 H mm; with low rear zip-tie loops ~41 D.
 //
 // Prototype assumptions to confirm against purchased parts:
 // - 1.3 inch OLED module/window opening: 31 x 16 mm visible window, 37 x 22 mm panel recess.
@@ -50,14 +50,19 @@ rocker_h = 19.0;
 front_slot_w = 34.0;         // two long rounded horizontal slots near lower front
 front_slot_h = 3.2;
 
-// Rear reusable cloth zip-tie / Velcro strap channels: low-profile external loops.
-strap_bridge_w = case_w - 14;
-strap_bridge_h = 6.5;        // outer raised rail height
-strap_slot_h = 4.2;          // strap thickness opening; adjust for cloth ties
-strap_gap_y = 2.4;           // clearance behind bridge for strap material
-strap_bridge_y = strap_gap_y + 2.4;
-strap_z1 = 23.0;
-strap_z2 = 50.0;
+// Rear reusable cloth zip-tie / Velcro pass-through loops.
+// Two visibly vertical external belt-loop brackets sit left/right of center.
+// The strap path is the real non-solid tunnel between rear wall and raised bridge;
+// it stays outside the electronics cavity and is open at the top/bottom for feeding.
+rear_loop_x = 13.0;
+rear_loop_w = 8.5;            // outside bracket width in X
+rear_loop_h = 50.0;           // outside bracket height in Z
+rear_loop_z = case_h/2;
+rear_loop_gap_y = 3.8;        // usable strap-thickness clearance behind raised bridge
+rear_loop_face_t = 1.4;       // low-profile outer bridge skin
+rear_loop_y = rear_loop_gap_y + rear_loop_face_t;
+rear_loop_usable_w = 6.4;     // usable strap width through each vertical loop
+rear_loop_side_pad = (rear_loop_w - rear_loop_usable_w) / 2;
 
 // USB power connector placeholder cutouts
 usb_c_cutout_w = 10.5;        // bottom USB-C female inlet visible opening, X width
@@ -107,24 +112,27 @@ module screw_boss(x, z) {
         }
 }
 
-module strap_bridge(zc) {
-    // Low external rear belt-loop bridge for cloth ties/Velcro.
-    // The slot is entirely behind the rear wall so it does not expose the
-    // electronics cavity; a small overlap keeps the bridge connected to shell.
-    bridge_overlap_y = 0.8;
-    translate([0, case_d/2 + strap_bridge_y/2 - bridge_overlap_y, zc - strap_bridge_h/2])
-        union() {
-            difference() {
-                rounded_box([strap_bridge_w, strap_bridge_y, strap_bridge_h], r=1.8);
-                translate([0, -strap_bridge_y/2 + bridge_overlap_y + 0.05 + (strap_bridge_y + 1.0)/2,
-                           (strap_bridge_h - strap_slot_h)/2])
-                    rounded_box([strap_bridge_w - 9.0, strap_bridge_y + 1.0, strap_slot_h], r=1.1);
-            }
+module rear_zip_tie_loop(xc) {
+    // Vertical external belt-loop bracket for reusable cloth zip ties/Velcro.
+    // The central void is a real strap tunnel: rear wall -> air gap -> raised
+    // outer bridge face. Side pads weld the bridge to the shell while keeping
+    // the electronics cavity sealed; the tunnel is open at top and bottom.
+    loop_overlap_y = 0.75;
+    tunnel_extra_y = 0.35;
+    tunnel_clear_z = rear_loop_h + 0.8;
 
-            // Rear-wall weld pad: mechanically joins the external bridge to the
-            // shell while keeping the belt slot outside the electronics cavity.
-            translate([0, -strap_bridge_y/2 + bridge_overlap_y, strap_bridge_h/2])
-                cube([strap_bridge_w, 0.9, strap_bridge_h], center=true);
+    translate([xc, case_d/2 + rear_loop_y/2 - loop_overlap_y, rear_loop_z])
+        difference() {
+            xz_rounded_prism(rear_loop_w, rear_loop_y, rear_loop_h, r=1.6);
+
+            // Real vertical feed-through gap behind the raised bridge.  Starts
+            // just outside the rear wall, so it cannot cut into the enclosure.
+            translate([0,
+                       -rear_loop_y/2 + loop_overlap_y + rear_loop_gap_y/2 + 0.08,
+                       0])
+                cube([rear_loop_usable_w,
+                      rear_loop_gap_y + tunnel_extra_y,
+                      tunnel_clear_z], center=true);
         }
 }
 
@@ -137,9 +145,9 @@ module camera_node_body_v4() {
                     // Upright outer shell with softened appliance-like corners.
                     rounded_box([case_w, case_d, case_h], r=corner_r);
 
-                    // Rear cloth zip-tie / Velcro strap bridges kept flat/quiet.
-                    strap_bridge(strap_z1);
-                    strap_bridge(strap_z2);
+                    // Rear cloth zip-tie / Velcro pass-through loops kept flat/quiet.
+                    rear_zip_tie_loop(-rear_loop_x);
+                    rear_zip_tie_loop( rear_loop_x);
                 }
 
                 // Full-height front recessed lid pocket, like the green reference panel.