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, 86 insertions, 0 deletions

diff --git a/apps/web/src/versions/store.ts b/apps/web/src/versions/store.ts
new file mode 100644
index 00000000..ae3f5d11
--- /dev/null
+++ b/apps/web/src/versions/store.ts
@@ -0,0 +1,86 @@
+import { IndexedDBAdapter } from "@/services/storage/indexeddb-adapter";
+import type { ProjectVersion } from "./types";
+
+/**
+ * Persistence backend for project versions. The IndexedDB implementation is
+ * the production store (its own database, created lazily — the v31→v32
+ * migration stamps project records); the in-memory implementation backs
+ * unit tests.
+ */
+export interface VersionStore {
+	put({ version }: { version: ProjectVersion }): Promise<void>;
+	getAllForProject({
+		projectId,
+	}: {
+		projectId: string;
+	}): Promise<ProjectVersion[]>;
+	delete({ id }: { id: string }): Promise<void>;
+	deleteForProject({ projectId }: { projectId: string }): Promise<void>;
+}
+
+export class IndexedDBVersionStore implements VersionStore {
+	private adapter = new IndexedDBAdapter<ProjectVersion>({
+		dbName: "video-editor-project-versions",
+		storeName: "project-versions",
+		version: 1,
+	});
+
+	async put({ version }: { version: ProjectVersion }): Promise<void> {
+		await this.adapter.set({ key: version.id, value: version });
+	}
+
+	async getAllForProject({
+		projectId,
+	}: {
+		projectId: string;
+	}): Promise<ProjectVersion[]> {
+		const all = await this.adapter.getAll();
+		return all.filter(
+			(version) =>
+				typeof version === "object" &&
+				version !== null &&
+				version.projectId === projectId,
+		);
+	}
+
+	async delete({ id }: { id: string }): Promise<void> {
+		await this.adapter.remove(id);
+	}
+
+	async deleteForProject({ projectId }: { projectId: string }): Promise<void> {
+		const versions = await this.getAllForProject({ projectId });
+		await Promise.all(
+			versions.map((version) => this.adapter.remove(version.id)),
+		);
+	}
+}
+
+export class InMemoryVersionStore implements VersionStore {
+	private versions = new Map<string, ProjectVersion>();
+
+	async put({ version }: { version: ProjectVersion }): Promise<void> {
+		this.versions.set(version.id, version);
+	}
+
+	async getAllForProject({
+		projectId,
+	}: {
+		projectId: string;
+	}): Promise<ProjectVersion[]> {
+		return [...this.versions.values()].filter(
+			(version) => version.projectId === projectId,
+		);
+	}
+
+	async delete({ id }: { id: string }): Promise<void> {
+		this.versions.delete(id);
+	}
+
+	async deleteForProject({ projectId }: { projectId: string }): Promise<void> {
+		for (const version of this.versions.values()) {
+			if (version.projectId === projectId) {
+				this.versions.delete(version.id);
+			}
+		}
+	}
+}