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/schema.ts

@@ -319,6 +319,7 @@ export const federationPeers = sqliteTable('federation_peers', {
   consecutiveFailures: integer('consecutive_failures').default(0),
   lastSyncedAt: integer('last_synced_at').default(0),
   remoteMaxUploadSize: integer('remote_max_upload_size'),
+  nonceSupported: integer('nonce_supported').notNull().default(0),
   createdAt: integer('created_at').notNull(),
 });