feat: add dashboard persistence store

src/lib/server/db/model-migrations.ts

@@ -0,0 +1,62 @@
+import {
+  DASHBOARD_SCHEMA_VERSION,
+  validateDashboardDocument,
+  type DashboardDocument,
+  type DashboardValidationFailure,
+} from "$lib/model";
+
+export interface DashboardModelMigrationSuccess {
+  valid: true;
+  document: DashboardDocument;
+  fromVersion: string;
+  toVersion: typeof DASHBOARD_SCHEMA_VERSION;
+  migrated: boolean;
+}
+
+export interface DashboardModelMigrationFailure {
+  valid: false;
+  failure: DashboardValidationFailure;
+}
+
+export type DashboardModelMigrationResult =
+  | DashboardModelMigrationFailure
+  | DashboardModelMigrationSuccess;
+
+export class UnsupportedDashboardModelVersionError extends Error {
+  constructor(
+    readonly fromVersion: string,
+    readonly toVersion: string,
+  ) {
+    super(`No dashboard model migration from ${fromVersion} to ${toVersion}`);
+    this.name = "UnsupportedDashboardModelVersionError";
+  }
+}
+
+export function migrateDashboardDocumentForPersistence(
+  value: unknown,
+): DashboardModelMigrationResult {
+  const version = readSchemaVersion(value);
+  if (version && version !== DASHBOARD_SCHEMA_VERSION) {
+    throw new UnsupportedDashboardModelVersionError(version, DASHBOARD_SCHEMA_VERSION);
+  }
+
+  const validation = validateDashboardDocument(value);
+  if (!validation.valid) {
+    return { valid: false, failure: validation };
+  }
+
+  return {
+    valid: true,
+    document: validation.data,
+    fromVersion: DASHBOARD_SCHEMA_VERSION,
+    toVersion: DASHBOARD_SCHEMA_VERSION,
+    migrated: false,
+  };
+}
+
+function readSchemaVersion(value: unknown): string | null {
+  if (!value || typeof value !== "object") return null;
+
+  const schemaVersion = (value as { schemaVersion?: unknown }).schemaVersion;
+  return typeof schemaVersion === "string" ? schemaVersion : null;
+}