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/drizzle/meta/_journal.json

@@ -22,6 +22,13 @@
       "when": 1793321456968,
       "tag": "0002_rooms",
       "breakpoints": true
+    },
+    {
+      "idx": 3,
+      "version": "7",
+      "when": 1793324955738,
+      "tag": "0003_products",
+      "breakpoints": true
     }
   ]
 }