Add cable_cap: e-paper nametag case with FPC exiting X- face

Display slides in from X+; FPC cable exits through a hull'd slot in the
closed X- wall with 2 mm side padding and full display-pocket height.

cable_cap.scad

@@ -0,0 +1,127 @@
+// Waveshare 2.13" e-Paper HAT (B) — ESP32 Nametag Case
+// Display slides in from X+; FPC cable exits out the closed X- face through a hull slot
+
+// --- Display Dimensions (landscape: portrait rotated 90°) ---
+DISP_W = 59.20;   // overall width  (X) — portrait height
+DISP_D = 29.20;   // overall depth  (Y) — portrait width
+DISP_T = 1.0;     // thickness      (Z)
+
+// --- Active (Visible) Area ---
+ACT_W  = 48.55;   // active area width (X) — portrait AA height
+ACT_D  = 23.71;   // active area depth (Y) — portrait AA width
+
+// Border offsets from display edge to active area:
+//   X-: portrait FPC border  ≈ 8.70 mm  (closed/backstop side — cable exits here)
+//   X+: portrait top border  ≈ 1.95 mm  (open/entry side)
+//   Y±: symmetric            ≈ 2.75 mm  each side
+ACT_X_OFFSET = 8.70;
+ACT_Y_OFFSET = 2.75;
+
+// --- FPC Cable (exits X- side) ---
+FPC_W   = 12.5;
+FPC_T   = 0.3;
+FPC_LEN = 20.0;   // visualization length of hanging tail
+
+// --- Case Parameters ---
+WALL       = 3.0;   // must exceed MAG_LIP_H (2.0) to keep pocket floor
+LIP        = 1.5;   // front bezel lip thickness (Z)
+TOL        = 0.3;   // per-side display clearance
+CHAM       = 1.0;
+CHAM_ANGLE = 60;
+CORNER_R   = 2.5;
+CLIP_Z     = 0;     // preview: mm to remove from Z+ (0 = full model)
+SHOW_DISP  = true;
+SCREEN_EXPLODE    = 0;     // mm to pull display toward X+ in preview
+
+// --- Magnetic Strip Locating Lip (rear face) ---
+MAG_L        = 1.772 * 25.4;   // strip length ≈ 45.01 mm
+MAG_W        = 0.512 * 25.4;   // strip width  ≈ 13.00 mm
+MAG_LIP_H    = 2.0;            // lip height protruding from rear face
+MAG_LIP_WALL = 1.0;            // lip wall thickness
+MAG_TOL      = 0.2;            // per-side clearance for strip fit
+
+// --- Derived Dimensions ---
+cav_w  = DISP_W + TOL * 2;
+cav_d  = DISP_D + TOL * 2;
+case_w = WALL + cav_w;          // no X+ wall; open for display entry
+case_h = WALL + DISP_T + LIP;
+case_d = WALL * 2 + cav_d;
+
+_cham_xy = CHAM * tan(CHAM_ANGLE);
+
+win_x = WALL + TOL + ACT_X_OFFSET;
+win_y = WALL + TOL + ACT_Y_OFFSET;
+
+// Magnetic strip recess geometry (centered on back face)
+_lip_il = MAG_L + 2 * MAG_TOL;
+_lip_iw = MAG_W + 2 * MAG_TOL;
+_lip_x  = case_w / 2 - _lip_il / 2;
+_lip_y  = case_d / 2 - _lip_iw / 2;
+
+// -------------------------------------------------------------------
+// Display mockup — approximate geometry for preview only
+// -------------------------------------------------------------------
+module EPD213B() {
+    color([0.82, 0.84, 0.80])
+        cube([DISP_W, DISP_D, DISP_T]);
+    color("white")
+        translate([ACT_X_OFFSET, ACT_Y_OFFSET, DISP_T])
+            cube([ACT_W, ACT_D, 0.02]);
+    color([1.0, 0.85, 0.1])
+        translate([-FPC_LEN, (DISP_D - FPC_W) / 2, (DISP_T - FPC_T) / 2])
+            cube([FPC_LEN, FPC_W, FPC_T]);
+}
+
+// -------------------------------------------------------------------
+
+module rounded_box(l, w, h, r) {
+    hull()
+        for (dx = [r, l-r], dy = [r, w-r])
+            translate([dx, dy, 0]) cylinder(r=r, h=h, $fn=32);
+}
+
+module epd_case() {
+    difference() {
+        rounded_box(case_w, case_d, case_h, CORNER_R);
+
+        // Display cavity — extends 0.01 mm past X+ face to leave that side open
+        translate([WALL, WALL, WALL])
+            cube([cav_w + 0.01, cav_d, DISP_T + TOL]);
+
+        // Active area window + chamfered top edges
+        translate([win_x, win_y, WALL + DISP_T - 0.01])
+            cube([ACT_W, ACT_D, LIP - CHAM + 0.02]);
+        hull() {
+            translate([win_x, win_y, case_h - CHAM])
+                cube([ACT_W, ACT_D, 0.01]);
+            translate([win_x - _cham_xy, win_y - _cham_xy, case_h])
+                cube([ACT_W + 2*_cham_xy, ACT_D + 2*_cham_xy, 0.01]);
+        }
+
+        // FPC slot through X- wall — hulled path, 2 mm padding each side of cable
+        hull() {
+            translate([-0.01, WALL + TOL + (DISP_D - FPC_W) / 2 - 2, WALL - 0.01])
+                cube([0.01, FPC_W + 4, DISP_T + TOL + 0.02]);
+            translate([WALL, WALL + TOL + (DISP_D - FPC_W) / 2 - 2, WALL - 0.01])
+                cube([0.01, FPC_W + 4, DISP_T + TOL + 0.02]);
+        }
+
+        // Magnetic strip recess in back face
+        translate([_lip_x, _lip_y, -0.01])
+            cube([_lip_il, _lip_iw, MAG_LIP_H + 0.01]);
+    }
+}
+
+color("#004B49")
+    intersection() {
+        epd_case();
+        cube([case_w + 1, case_d + 1,
+              ($preview && CLIP_Z > 0)
+                  ? max(0.01, case_h - CLIP_Z)
+                  : case_h + 1]);
+    }
+
+if ($preview && SHOW_DISP)
+    translate([WALL + TOL + SCREEN_EXPLODE, WALL + TOL, WALL])
+        EPD213B();
+