feat: git-like project versioning (v1)

Linear per-project history per notes/project-versioning.md: named
checkpoints (thumbnail via renderer.captureFrame) plus auto-checkpoints
on save (60s throttle, ring of 20, named never rotate). Restore writes a
safety checkpoint first, then swaps the document outside undo/redo.
Media assets referenced by any version are pinned against deletion.
Migration v31-v32 stamps the schema; the version store lives in its own
IDB database with an in-memory fallback for tests. Versions popover in
the editor header for jump/rename/delete. 12 new tests.

1 files changed, 65 insertions, 0 deletions

diff --git a/apps/web/src/services/storage/migrations/__tests__/v31-to-v32.test.ts b/apps/web/src/services/storage/migrations/__tests__/v31-to-v32.test.ts
new file mode 100644
index 00000000..e3f1af8c
--- /dev/null
+++ b/apps/web/src/services/storage/migrations/__tests__/v31-to-v32.test.ts
@@ -0,0 +1,65 @@
+import { describe, expect, test } from "bun:test";
+import { transformProjectV31ToV32 } from "../transformers/v31-to-v32";
+import { asRecord, asRecordArray } from "./helpers";
+
+describe("V31 to V32 Migration", () => {
+	test("stamps a v31 project as v32 without changing its content", () => {
+		const result = transformProjectV31ToV32({
+			project: {
+				id: "project-v31",
+				version: 31,
+				metadata: { id: "project-v31", name: "My project" },
+				scenes: [
+					{
+						id: "scene-1",
+						tracks: {
+							main: {
+								id: "track-1",
+								type: "video",
+								elements: [{ id: "elem-1", type: "video", mediaId: "media-1" }],
+							},
+							overlay: [],
+							audio: [],
+						},
+					},
+				],
+			},
+		});
+
+		expect(result.skipped).toBe(false);
+		expect(result.project.version).toBe(32);
+		const scene = asRecordArray(result.project.scenes)[0];
+		const main = asRecord(asRecord(scene.tracks).main);
+		const element = asRecordArray(main.elements)[0];
+		expect(element).toMatchObject({
+			id: "elem-1",
+			type: "video",
+			mediaId: "media-1",
+		});
+		expect(asRecord(result.project.metadata).name).toBe("My project");
+	});
+
+	test("skips a project that is already v32", () => {
+		const project = { id: "p1", version: 32, scenes: [] };
+		const result = transformProjectV31ToV32({ project });
+		expect(result.skipped).toBe(true);
+		expect(result.reason).toBe("already v32");
+		expect(result.project).toBe(project);
+	});
+
+	test("skips a project that is not v31", () => {
+		const project = { id: "p1", version: 30, scenes: [] };
+		const result = transformProjectV31ToV32({ project });
+		expect(result.skipped).toBe(true);
+		expect(result.reason).toBe("not v31");
+		expect(result.project).toBe(project);
+	});
+
+	test("skips a project without an id", () => {
+		const project = { version: 31, scenes: [] };
+		const result = transformProjectV31ToV32({ project });
+		expect(result.skipped).toBe(true);
+		expect(result.reason).toBe("no project id");
+		expect(result.project).toBe(project);
+	});
+});