Fix Z-axis cap bore tolerances to CAP_TOL on both faces

_cap_bore_h was case_h + 2*CAP_TOL, giving 2x clearance above and 0x
below. Fix: set _cap_bore_h = case_h + CAP_TOL and deepen the Z- case
recess from CAP_WALL to CAP_WALL + CAP_TOL, giving 1x CAP_TOL on each face.

cable_cap.scad

@@ -74,7 +74,7 @@ fpc_pkt_yw = FPC_W + 2 * FPC_POCKET_PAD;
 
 // Cap derived
 _cap_bore_w  = case_d - 2*CAP_WALL;                // bore Y width (fits recessed case)
-_cap_bore_h  = case_h + 2*CAP_TOL;                 // bore Z height
+_cap_bore_h  = case_h + CAP_TOL;                   // bore Z height (CAP_TOL clearance on each Z face)
 _cap_gap_w   = (case_w - CAP_ENGAGE + CAP_PAD) - (win_x + ACT_W + _cham_xy); // gap between cap X- face and beveled bezel X+ end
 // Magnetic strip recess geometry (centered on back face)
 _lip_il = MAG_L + 2 * MAG_TOL;
@@ -132,7 +132,7 @@ module epd_case() {
 
         // Cap wall recess — step in z- face at X+ end so cap sits flush
         translate([case_w - CAP_ENGAGE + CAP_PAD, -0.01, -0.01])
-            cube([CAP_ENGAGE + 0.02 - CAP_PAD, case_d + 0.02, CAP_WALL + 0.01]);
+            cube([CAP_ENGAGE + 0.02 - CAP_PAD, case_d + 0.02, CAP_WALL + CAP_TOL + 0.01]);
 
         // Cap wall recess — step in y- face at X+ end so cap sits flush
         translate([case_w - CAP_ENGAGE + CAP_PAD, -0.01, -0.01])