Product registry: catalogs, revisions, product info and libraries

The hub registers catalogs (hidden until a moderator approves them), hands out upload tokens, and records the
revisions catalogs register after validating uploads: numbered, never changed, signed by the hub (its own
Ed25519 key, published at /.well-known/t5de-keys.json). Creators edit product info (descriptions cleaned by an
allowlist) and can retract revisions. People get products into their library, optionally staying on a
revision; the proxy asks which revision to load and where. Contract in docs/products.md.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/db/src/index.ts

@@ -11,6 +11,7 @@ import { fileURLToPath } from "node:url";
 import * as schema from "./schema";
 
 export { schema };
+export type { FileEntry } from "./schema";
 export * from "drizzle-orm";
 
 const migrationsFolder = fileURLToPath(new URL("../drizzle", import.meta.url));