feat(federation): add nonceSupported column to federation_peers (FED-008)

Adds nonce_supported INTEGER column to the federation_peers table in both
the Drizzle schema definition and via a safe ALTER TABLE migration, enabling
the auto-ratchet mechanism for replay attack protection.

packages/server/src/db/migrate.ts

@@ -2098,4 +2098,9 @@ function migrateGeneralizeOutbox(db: Database.Database): void {
       db.exec(`PRAGMA foreign_keys = ON`);
     }
   }
+
+  // ─── FED-008: Add nonceSupported column for replay attack protection ───────
+  try {
+    db.exec(`ALTER TABLE federation_peers ADD COLUMN nonce_supported INTEGER NOT NULL DEFAULT 0`);
+  } catch { /* column already exists */ }
 }