Dächer: Platzier-Werkzeug + 2D-Plan + 3D-Flächen + Demo-Dach

Dach-Feature end-to-end nutzbar:
- Befehl „Dach" (Alias dach/rf, BIM-Ribbon, Satteldach-Icon): Grundriss als
  Rechteck aufziehen; die Dachform (Sattel/Walm/Pult/Mansarde/Zelt/Flach)
  wählt man als Inline-Option der Befehlszeile vor/während des Aufziehens.
  First entlang der längeren Seite (Standard).
- 2D-Grundriss (generatePlan): Traufe/First/Grat (Walm/Zelt) + gestrichelte
  Knicklinien (Mansarde), Farbe aus roof.color/Kategorie „31 Dächer".
- 3D (toWalls3d emitRoofs): Dachflächen + Giebel als terrakottafarbene
  Meshes (Fan-Triangulierung, Mansarde-Fünfeck sauber).
- Seed: Demo-Satteldach RF1 über dem Baukörper (OG, 5×4, Überstand 0.4).
- i18n de/en für Befehl + Formen.

+10 Tests (2D 7, 3D 3). tsc + vitest 640 grün. Auswahl/Attribut-Editieren
placierter Dächer folgt separat.

src/plan/generatePlan.roof.test.ts

@@ -0,0 +1,147 @@
+/**
+ * Unit-Tests für die Dach-Darstellung im Grundriss (generatePlan → addRoof):
+ * `project.roofs` wird nach Geschoss + sichtbarer Kategorie gefiltert (analog
+ * Decken) und pro Dach in Grundriss-Linien übersetzt (Traufe/First/Grat/Knick,
+ * aus `roofGeometry`). Reine Linien-Darstellung ohne Poché — die Form (flach/
+ * sattel/walm/mansarde) entscheidet, welche der vier Linienarten auftauchen.
+ */
+
+import { describe, it, expect } from "vitest";
+import { generatePlan } from "./generatePlan";
+import type { Project, Roof } from "../model/types";
+
+/** Minimalprojekt ohne Wände: nur das Geschoss + die Dach-Kategorie „35". */
+function baseProject(roofs?: Roof[]): Project {
+  return {
+    id: "t",
+    name: "T",
+    lineStyles: [],
+    hatches: [],
+    components: [],
+    wallTypes: [],
+    drawingLevels: [
+      {
+        id: "eg",
+        name: "EG",
+        kind: "floor",
+        visible: true,
+        locked: false,
+        floorHeight: 2.6,
+        cutHeight: 1.0,
+        baseElevation: 0,
+      },
+    ],
+    layers: [{ code: "35", name: "Dächer", color: "#8a4b32", lw: 0.25, visible: true, locked: false }],
+    walls: [],
+    doors: [],
+    openings: [],
+    ceilings: [],
+    stairs: [],
+    rooms: [],
+    drawings2d: [],
+    context: [],
+    ...(roofs !== undefined ? { roofs } : {}),
+  };
+}
+
+const rectOutline: Roof["outline"] = [
+  { x: 0, y: 0 },
+  { x: 6, y: 0 },
+  { x: 6, y: 4 },
+  { x: 0, y: 4 },
+];
+
+const roof = (id: string, shape: Roof["shape"], extra: Partial<Roof> = {}): Roof => ({
+  id,
+  type: "roof",
+  floorId: "eg",
+  categoryCode: "35",
+  outline: rectOutline,
+  shape,
+  pitchDeg: 30,
+  overhang: 0.5,
+  ridgeAxis: "x",
+  thickness: 0.3,
+  ...extra,
+});
+
+const visible = new Set(["35"]);
+
+/** Filtert die Grundriss-Primitive nach `kind:"line"` + gegebener Klasse. */
+function linesOf(primitives: ReturnType<typeof generatePlan>["primitives"], cls: string) {
+  return primitives.filter(
+    (p): p is Extract<typeof p, { kind: "line" }> => p.kind === "line" && p.cls === cls,
+  );
+}
+
+describe("generatePlan — Dächer (Dachaufsicht)", () => {
+  it("Satteldach: Traufe + First, aber kein Grat/Knick", () => {
+    const plan = generatePlan(baseProject([roof("R1", "sattel")]), "eg", visible);
+    expect(linesOf(plan.primitives, "roof-eaves").length).toBeGreaterThan(0);
+    expect(linesOf(plan.primitives, "roof-ridge").length).toBeGreaterThan(0);
+    expect(linesOf(plan.primitives, "roof-hip").length).toBe(0);
+    expect(linesOf(plan.primitives, "roof-break").length).toBe(0);
+  });
+
+  it("Walmdach: Traufe + First + Grat", () => {
+    const plan = generatePlan(baseProject([roof("R2", "walm")]), "eg", visible);
+    expect(linesOf(plan.primitives, "roof-eaves").length).toBeGreaterThan(0);
+    expect(linesOf(plan.primitives, "roof-ridge").length).toBeGreaterThan(0);
+    expect(linesOf(plan.primitives, "roof-hip").length).toBeGreaterThan(0);
+  });
+
+  it("Mansarddach: Knicklinien gestrichelt", () => {
+    const plan = generatePlan(baseProject([roof("R3", "mansarde")]), "eg", visible);
+    const breaks = linesOf(plan.primitives, "roof-break");
+    expect(breaks.length).toBeGreaterThan(0);
+    for (const b of breaks) {
+      expect(b.dash).toBeTruthy();
+      expect(b.dash?.length).toBeGreaterThan(0);
+    }
+  });
+
+  it("Flachdach: nur Traufe, weder First noch Grat noch Knick", () => {
+    const plan = generatePlan(baseProject([roof("R4", "flach")]), "eg", visible);
+    expect(linesOf(plan.primitives, "roof-eaves").length).toBeGreaterThan(0);
+    expect(linesOf(plan.primitives, "roof-ridge").length).toBe(0);
+    expect(linesOf(plan.primitives, "roof-hip").length).toBe(0);
+    expect(linesOf(plan.primitives, "roof-break").length).toBe(0);
+  });
+
+  it("First-Linie ist kräftiger als die Traufe (First > Traufe > Knick)", () => {
+    const plan = generatePlan(baseProject([roof("R5", "mansarde")]), "eg", visible);
+    const eaves = linesOf(plan.primitives, "roof-eaves")[0];
+    const ridge = linesOf(plan.primitives, "roof-ridge")[0];
+    const brk = linesOf(plan.primitives, "roof-break")[0];
+    expect(ridge.weightMm).toBeGreaterThan(eaves.weightMm);
+    expect(eaves.weightMm).toBeGreaterThan(brk.weightMm);
+  });
+
+  it("löst die Strichfarbe über roof.color, sonst die Kategorie-Farbe auf", () => {
+    const withColor = generatePlan(
+      baseProject([roof("R6", "sattel", { color: "#ff0000" })]),
+      "eg",
+      visible,
+    );
+    expect(linesOf(withColor.primitives, "roof-eaves")[0].color).toBe("#ff0000");
+
+    const withoutColor = generatePlan(baseProject([roof("R7", "sattel")]), "eg", visible);
+    expect(linesOf(withoutColor.primitives, "roof-eaves")[0].color).toBe("#8a4b32");
+  });
+
+  it("Rückwärtskompatibilität: ohne Dächer (bzw. Dach auf anderem Geschoss) bleiben die Primitive unverändert", () => {
+    const planNoField = generatePlan(baseProject(undefined), "eg", visible);
+    const planEmpty = generatePlan(baseProject([]), "eg", visible);
+    const planOtherFloor = generatePlan(
+      baseProject([roof("R8", "sattel", { floorId: "og" })]),
+      "eg",
+      visible,
+    );
+
+    expect(planEmpty.primitives).toEqual(planNoField.primitives);
+    expect(planOtherFloor.primitives).toEqual(planNoField.primitives);
+    expect(planNoField.primitives.some((p) => p.kind === "line" && p.cls.startsWith("roof-"))).toBe(
+      false,
+    );
+  });
+});