feat(bots): bot framework polish + store

- /ws/bot endpoint: bot token auth via query param, SHA-256 lookup
- Bot WS actions: SEND_MESSAGE + DELETE_MESSAGE handled in gateway
- Bot messages: bot_id on messages table, bot badge in chat (green + BOT tag)
- Bot store: /bots lists all bots with server count + add-to-server
- Bot manager moved to /bots/manage
- Fix: command routes were double-nested under /bots/{botID}/commands
- Fix: fetchServerCommands route corrected to /bots/servers/...

web/src/components/BotManager.tsx

@@ -348,8 +348,8 @@ export function BotManager() {
 
           {/* Footer */}
           <div className="mt-6 pt-4 border-t border-gb-bg-t">
-            <Link to="/" className="text-gb-fg-f hover:text-gb-aqua font-mono text-sm">
-              {'<'} [BACK TO CHAT]
+            <Link to="/bots" className="text-gb-fg-f hover:text-gb-aqua font-mono text-sm">
+              {'<'} [BACK TO STORE]
             </Link>
           </div>
         </div>