Fix cap Z alignment: flush with case Z- floor

Remove -CAP_TOL Z offset from cap translate; the recess in the case
already provides the fit at Z-, so the offset was dropping the cap
0.2mm below the case floor.

cable_cap.scad

@@ -145,7 +145,7 @@ module cable_cap() {
     _bore_h = _cap_bore_h - CAP_WALL;
     _bore_r = _bore_h / 2;
 
-    translate([case_w - CAP_ENGAGE + CAP_EXPLODE, -CAP_TOL - CAP_WALL, -CAP_TOL]){
+    translate([case_w - CAP_ENGAGE + CAP_EXPLODE, -CAP_TOL - CAP_WALL, 0]){
     difference() {
         // Outer shell: hull between two square profiles
         hull() {