Cut list accounts for protruding tenons

A tenon adds length beyond the board's end, so the real piece you cut is longer
than length_in. cutlist.cut_length() now adds end-tenon protrusions to the cut
length used by the cut list, board-feet, and the buy-list (subtractive features
like mortises/holes don't change the stock you buy, so they're ignored). The
cut list notes when lengths include tenons.

70 tests pass (end-tenon extends cut length; cut features don't).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/woodshop/cutlist.py

@@ -29,6 +29,15 @@ def board_feet(stock: str, length_in: float) -> float:
     return t * w * length_in / 144.0
 
 
+def cut_length(part) -> float:
+    """The length to cut the board to, including any tenon that protrudes past an
+    end. Subtractive features (mortise/hole/slot/chamfer) don't change the stock
+    length you buy, so they're ignored here."""
+    extra = sum(f.depth_in for f in part.features
+                if f.kind == "tenon" and f.face in ("end_a", "end_b"))
+    return part.length_in + extra
+
+
 def _fmt_len(inches: float) -> str:
     feet, rem = divmod(round(inches, 2), 12)
     if feet and rem:
@@ -39,10 +48,10 @@ def _fmt_len(inches: float) -> str:
 
 
 def cut_rows(scene: Scene) -> list[dict]:
-    """One row per distinct (stock, length), with a count."""
+    """One row per distinct (stock, cut-length), with a count."""
     groups: dict[tuple[str, float], int] = defaultdict(int)
     for p in scene.parts:
-        groups[(p.stock, round(p.length_in, 2))] += 1
+        groups[(p.stock, round(cut_length(p), 2))] += 1
     rows = []
     for (stock, length), count in sorted(groups.items()):
         rows.append({
@@ -56,7 +65,7 @@ def shopping(scene: Scene) -> dict[str, int]:
     """Sticks of standard length to buy per stock (by total length, +10% waste)."""
     total: dict[str, float] = defaultdict(float)
     for p in scene.parts:
-        total[p.stock] += p.length_in
+        total[p.stock] += cut_length(p)
     return {stock: math.ceil(length * 1.10 / STICK_LENGTH_IN)
             for stock, length in sorted(total.items())}
 
@@ -71,6 +80,8 @@ def format_cutlist(scene: Scene) -> str:
                      f"  ({r['board_feet']:.1f} bd-ft)")
     total_bf = sum(r["board_feet"] for r in rows)
     lines.append(f"  Total: {len(scene.parts)} board(s), {total_bf:.1f} board-feet")
+    if any(cut_length(p) > p.length_in for p in scene.parts):
+        lines.append("  (cut lengths include protruding tenons)")
     lines.append("SHOPPING (8' sticks, +10% waste)")
     for stock, sticks in shopping(scene).items():
         lines.append(f"  {sticks} × {stock}")

tests/test_cutlist.py

@@ -36,3 +36,23 @@ def test_shopping_rounds_up_with_waste():
 
 def test_empty_shopping():
     assert shopping(Scene()) == {}
+
+
+def test_end_tenon_extends_cut_length():
+    from woodshop.cutlist import cut_length
+    s = Scene()
+    s.place("2x4", 24)
+    assert cut_length(s.get_part("p1")) == 24
+    s.add_feature("p1", "tenon", face="end_b", depth_in=1.5)   # protrudes 1.5"
+    assert cut_length(s.get_part("p1")) == 25.5
+    # the cut row and board-feet reflect the longer piece
+    assert cut_rows(s)[0]["length_in"] == 25.5
+    assert cut_rows(s)[0]["board_feet"] == pytest.approx(board_feet("2x4", 25.5))
+
+
+def test_cut_feature_does_not_change_cut_length():
+    from woodshop.cutlist import cut_length
+    s = Scene()
+    s.place("2x4", 24)
+    s.add_feature("p1", "mortise", face="top", width_in=1, height_in=1, depth_in=0.5)
+    assert cut_length(s.get_part("p1")) == 24   # cuts don't reduce stock you buy