Sheet metal: a hole drilled into a rim is a bore its panel keeps (#560) (#955)

A hole drilled along a panel, into its rim, has no place in the flat pattern
as a cut-out, so every such hole was refused. It is now kept as a bore of that
panel, in flat coordinates, and cut only from that panel's material when the
folded part and its flat pattern are built, so the sheet still unfolds and
folds back with it. A hole that would run into a bend, or cross a panel at an
angle, is still refused. The flat pattern lists the bores.

The action matrix worker takes ACTION_MATRIX_ONLY (just these actions) and
ACTION_MATRIX_UNFOLD (unfold and refold every sheet after each action) for
rechecking one group by hand.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/sheet.rs

@@ -436,9 +436,17 @@ fn flat_json(sh: &SheetBody) -> Result<Value> {
             "side": side, "depth_mm": p.z1-p.z0, "z0_mm": p.z0, "z1_mm": p.z1})
         })
         .collect();
-    Ok(
-        json!({"body": sh.body, "rule": sh.rule, "thickness": sh.t, "k_factor": sh.k, "flat_size_mm": [w, h, sh.t], "outline": outline, "cutouts": holes, "cutout_shapes": hole_shapes, "pockets": pockets, "bends": bends, "unfolded": sh.flat}),
-    )
+    // Holes drilled along a panel into its rim: drilled after cutting, not in the outline.
+    let bores: Vec<Value> = sh
+        .bores
+        .iter()
+        .map(|b| json!({"start": [b.base.x, b.base.y, b.base.z], "axis": [b.axis.x, b.axis.y, b.axis.z], "diameter": b.radius * 2.0, "length": b.height.abs()}))
+        .collect();
+    let mut out = json!({"body": sh.body, "rule": sh.rule, "thickness": sh.t, "k_factor": sh.k, "flat_size_mm": [w, h, sh.t], "outline": outline, "cutouts": holes, "cutout_shapes": hole_shapes, "pockets": pockets, "bends": bends, "unfolded": sh.flat});
+    if !bores.is_empty() {
+        out["bores"] = Value::Array(bores);
+    }
+    Ok(out)
 }
 
 fn flat_pattern(s: &mut Session, p: &Value) -> Result<Value> {