feat: add named canvas presets with YouTube Shorts entry

Introduces NAMED_CANVAS_PRESETS with id/label/aspectRatio/projectType metadata so the UI can show meaningful preset names (e.g. "YouTube Shorts (1080×1920)") and so downstream code can resolve a preset by intent rather than dimensions.

- NAMED_CANVAS_PRESETS: landscape 16:9, YouTube Shorts 9:16, square, landscape 4:3
- SHORTS_CANVAS_PRESET convenience export for 9:16 vertical
- DEFAULT_CANVAS_PRESETS preserved (derived from NAMED) so existing editor-store consumers keep working
- Unit tests verify shape, ordering, and back-compat derivation

apps/web/src/canvas/__tests__/sizes.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, test } from "bun:test";
+import {
+	DEFAULT_CANVAS_PRESETS,
+	DEFAULT_CANVAS_SIZE,
+	NAMED_CANVAS_PRESETS,
+	SHORTS_CANVAS_PRESET,
+} from "@/canvas/sizes";
+
+describe("NAMED_CANVAS_PRESETS", () => {
+	test("has the four canonical presets in declared order", () => {
+		const ids = NAMED_CANVAS_PRESETS.map((p) => p.id);
+		expect(ids).toEqual([
+			"landscape-1080p",
+			"shorts-1080x1920",
+			"square-1080",
+			"landscape-1440",
+		]);
+	});
+
+	test("every preset has consistent shape", () => {
+		for (const preset of NAMED_CANVAS_PRESETS) {
+			expect(preset.id.length).toBeGreaterThan(0);
+			expect(preset.label.length).toBeGreaterThan(0);
+			expect(preset.size.width).toBeGreaterThan(0);
+			expect(preset.size.height).toBeGreaterThan(0);
+			expect(preset.aspectRatio).toMatch(/^\d+:\d+$/);
+		}
+	});
+});
+
+describe("SHORTS_CANVAS_PRESET", () => {
+	test("is 1080x1920 vertical 9:16", () => {
+		expect(SHORTS_CANVAS_PRESET.size).toEqual({ width: 1080, height: 1920 });
+		expect(SHORTS_CANVAS_PRESET.aspectRatio).toBe("9:16");
+		expect(SHORTS_CANVAS_PRESET.projectType).toBe("shorts");
+	});
+});
+
+describe("DEFAULT_CANVAS_PRESETS (back-compat)", () => {
+	test("derives from NAMED_CANVAS_PRESETS in order", () => {
+		expect(DEFAULT_CANVAS_PRESETS).toEqual(
+			NAMED_CANVAS_PRESETS.map((p) => p.size),
+		);
+	});
+
+	test("contains the Shorts preset 1080x1920", () => {
+		expect(DEFAULT_CANVAS_PRESETS).toContainEqual({
+			width: 1080,
+			height: 1920,
+		});
+	});
+});
+
+describe("DEFAULT_CANVAS_SIZE", () => {
+	test("remains 1920x1080 (landscape default)", () => {
+		expect(DEFAULT_CANVAS_SIZE).toEqual({ width: 1920, height: 1080 });
+	});
+});

apps/web/src/canvas/sizes.ts

@@ -1,10 +1,63 @@
-import type { TCanvasSize } from "@/project/types";
+import type { TCanvasSize, TProjectType } from "@/project/types";
 
-export const DEFAULT_CANVAS_PRESETS: TCanvasSize[] = [
-	{ width: 1920, height: 1080 },
-	{ width: 1080, height: 1920 },
-	{ width: 1080, height: 1080 },
-	{ width: 1440, height: 1080 },
+/**
+ * A canvas preset bundles the raw size with display metadata (label,
+ * aspect ratio) and the project intent it implies. UIs should prefer
+ * NAMED_CANVAS_PRESETS when rendering preset pickers; consumers that
+ * only need the size array continue to use DEFAULT_CANVAS_PRESETS.
+ */
+export interface TCanvasPreset {
+	id: string;
+	label: string;
+	size: TCanvasSize;
+	aspectRatio: string;
+	projectType?: TProjectType;
+}
+
+export const NAMED_CANVAS_PRESETS: readonly TCanvasPreset[] = [
+	{
+		id: "landscape-1080p",
+		label: "Landscape 1920×1080",
+		size: { width: 1920, height: 1080 },
+		aspectRatio: "16:9",
+		projectType: "standard",
+	},
+	{
+		id: "shorts-1080x1920",
+		label: "YouTube Shorts (1080×1920)",
+		size: { width: 1080, height: 1920 },
+		aspectRatio: "9:16",
+		projectType: "shorts",
+	},
+	{
+		id: "square-1080",
+		label: "Square 1080×1080",
+		size: { width: 1080, height: 1080 },
+		aspectRatio: "1:1",
+		projectType: "standard",
+	},
+	{
+		id: "landscape-1440",
+		label: "Landscape 1440×1080",
+		size: { width: 1440, height: 1080 },
+		aspectRatio: "4:3",
+		projectType: "standard",
+	},
 ];
 
-export const DEFAULT_CANVAS_SIZE: TCanvasSize = { width: 1920, height: 1080 };
+/**
+ * Convenience reference to the YouTube Shorts preset.
+ */
+export const SHORTS_CANVAS_PRESET: TCanvasPreset = NAMED_CANVAS_PRESETS.find(
+	(p) => p.id === "shorts-1080x1920",
+)!;
+
+/**
+ * Back-compat: existing consumers (editor-store, etc.) read a bare
+ * TCanvasSize[]. Derived from NAMED_CANVAS_PRESETS to keep them in sync.
+ */
+export const DEFAULT_CANVAS_PRESETS: TCanvasSize[] = NAMED_CANVAS_PRESETS.map(
+	(p) => p.size,
+);
+
+export const DEFAULT_CANVAS_SIZE: TCanvasSize = NAMED_CANVAS_PRESETS[0].size;