Improve worker error logging and update Dokploy deployment docs

docs/discord-integration.md

@@ -1,7 +1,7 @@
 # Discord announcements
 
 MineGeo uses your Discord bot to send messages through Discord's REST API.
-It runs on Vercel and does not need a continuously running bot process, Gateway,
+It does not need a continuously running bot process, Gateway,
 Message Content intent, slash commands, an interactions URL, or a Discord webhook.
 The bot can appear offline while announcements work.
 
@@ -28,7 +28,7 @@ a transfer of lobby ownership. The counts are a snapshot when posted.
 1. Open the [Discord Developer Portal](https://discord.com/developers/applications)
    and select **New Application**. Name it **MineGeo**, or your preferred bot name.
 2. Open **Bot**. Create the bot if prompted, then use **Reset Token** to obtain
-   its bot token. Keep it private; save it directly into Vercel as described below.
+   its bot token. Keep it private; save it directly in Dokploy as described below.
 3. Under **Installation**, enable **Guild Install**. For the guild's install
    settings, choose the **bot** scope and these permissions: **View Channels**,
    **Send Messages**, **Embed Links**. You do not need Administrator permission.
@@ -46,10 +46,9 @@ a transfer of lobby ownership. The counts are a snapshot when posted.
 Discord setup references: [application setup](https://docs.discord.com/developers/quick-start/getting-started),
 [bot permissions](https://docs.discord.com/developers/topics/permissions).
 
-## Add the Vercel environment variables
+## Add the Dokploy environment variables
 
-Open [MineGeo's environment settings](https://vercel.com/pavel-melnikovs-projects-74f979c2/minegeo/settings/environment-variables).
-Add these for **Production**:
+In Dokploy, open the MineGeo application's **Environment** settings and add:
 
 | Name | Value | Sensitive? |
 | --- | --- | --- |
@@ -63,9 +62,8 @@ Leave a channel variable blank to disable that announcement type. A Discord
 invite such as `MINEGEO_DISCORD_URL` controls the footer button only; it cannot
 send announcements.
 
-After saving, open **Deployments**, choose the newest Production deployment,
-select **Redeploy**, and use the current environment variables. Vercel applies
-environment changes to new deployments. See [Vercel's environment-variable guide](https://vercel.com/docs/environment-variables).
+After saving, redeploy the MineGeo application so the server uses the new
+environment values.
 
 For local use, put the same variables in ignored `.env.local` (ordinary `.env`
 also works) and restart the server. Use a publicly reachable HTTPS `MINEGEO_URL`