Remove vestigial FPC exit slot variables

_cap_slot_w and _cap_slot_h were computed but never used; the exit slot
concept was replaced by internal 180° cable routing. Also restore
CAP_EXPLODE preview offset to CAP_PAD + 10.

cable_cap.scad

@@ -46,7 +46,7 @@ CAP_PAD     = 4.0;   // Min cap bore depth
 CAP_ENGAGE  = CAP_PAD + 6.0;   // sleeve engagement length over case exterior (X)
 CAP_WALL    = 1.5;   // sleeve and end-wall thickness
 CAP_TOL     = 0.2;   // per-side slip clearance between bore and case exterior
-CAP_EXPLODE = CAP_PAD + 0;     // preview: mm to pull cap away from case in X+ (0 = seated)
+CAP_EXPLODE = CAP_PAD + 10;     // preview: mm to pull cap away from case in X+ (0 = seated)
 
 // --- Magnetic Strip Locating Lip (rear face) ---
 MAG_L        = 1.772 * 25.4;   // strip length ≈ 45.01 mm
@@ -74,10 +74,6 @@ 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
-// FPC exit slot spans the full FPC pocket height (pocket floor → cavity ceiling)
-_cap_slot_w  = FPC_W + 1.0;                                       // slot Y width
-_cap_slot_h  = FPC_FLOOR_DROP + DISP_T + TOL + 2 * CAP_TOL;      // slot Z height
-
 // Magnetic strip recess geometry (centered on back face)
 _lip_il = MAG_L + 2 * MAG_TOL;
 _lip_iw = MAG_W + 2 * MAG_TOL;