feat(db): mesh data model — meshes, members, invites, audit log

- pgSchema "mesh" with 4 tables isolating the peer mesh domain
- Enums: visibility, transport, tier, role
- audit_log is metadata-only (E2E encryption enforced at broker/client)
- Cascade on mesh delete, soft-delete via archivedAt/revokedAt

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared/src/utils/exceptions.ts

@@ -0,0 +1,32 @@
+import { HttpStatusCode } from "../constants";
+
+export const isHttpStatus = (status: number): status is HttpStatusCode =>
+  Object.values<number>(HttpStatusCode).includes(status);
+
+interface HttpExceptionOptions {
+  message?: string;
+  code?: string;
+}
+
+export class HttpException extends Error {
+  readonly status?: HttpStatusCode;
+  readonly code?: string;
+
+  constructor(status?: HttpStatusCode, options?: HttpExceptionOptions) {
+    super(options?.message);
+    this.status = status;
+    this.code = options?.code;
+  }
+}
+
+export const getStatusCode = (e: unknown) => {
+  if (typeof e === "object" && e && "status" in e) {
+    const status = Number(e.status);
+    // Guard against NaN or invalid status codes
+    if (!Number.isNaN(status) && status >= 200 && status <= 599) {
+      return status;
+    }
+  }
+
+  return HttpStatusCode.INTERNAL_SERVER_ERROR;
+};