feat(discord): add Discord notification bot service (#6486)

* feat(discord): add Discord notification bot service, settings UI, and event subscriber
- internal/web/service/discord: implement lightweight Discord REST API v10 client and EventBus subscriber
- internal/web/service/setting: add discordBotEnable, discordBotToken, discordChannelId, discordEnabledEvents, discordCpu, discordMemory settings and secret protection
- internal/web/controller: register POST /panel/api/setting/testDiscord endpoint
- frontend: add Discord settings tab, notifications configuration, sidebar navigation, and command palette integration
- translation: add localization keys across all 13 locales
- tests: add comprehensive unit tests with httptest server and verify route/i18n contracts

* fix(discord): address PR review findings on concurrency, linting, i18n, and stories

- subscriber: eliminate unbounded goroutines, sending inline per EventBus contract
- discord: accept context.Context in SendMessage, SendEmbed, SendTest with http.NewRequestWithContext
- format: apply gofumpt to controller and entity struct alignments
- i18n: localize testDiscord controller responses across all 13 locales
- storybook: add DiscordNotifications.stories.tsx component story

* docs: add Discord bot setup and operations guide

- add docs/content/docs/en/operations/discord-bot.mdx with setup steps, event indicators, settings, and troubleshooting
- add docs/content/docs/ru/operations/discord-bot.mdx with localized instructions
- update operations/meta.json across en, ru, zh, fa
- link Discord bot from panel configuration overview

* feat(discord): add discordLang, discordRunTime, discordBotBackup settings and update settings UI

- internal/web/entity: add DiscordRunTime, DiscordBotBackup, DiscordLang fields to AllSetting
- internal/web/service/setting: add defaultValueMap entries, getters, and setters
- frontend: update AllSetting schema, model defaults, and generate OpenAPI / Zod contracts
- frontend: extract shared NotifyTimeField component and update DiscordTab with General and Notifications tabs
- translation: add localization keys across all 13 locales

* feat(discord): implement scheduled status reports and database backup attachments

- internal/web/service/discord: add SendMessageWithFiles supporting multipart uploads
- internal/web/service/discord: implement BuildReport and SendReport generating rich status embeds
- internal/web/service/discord: attach database backup (and config.json) when discordBotBackup is enabled
- internal/web/job: implement DiscordNotifyJob scheduled via robfig/cron
- internal/web/locale: add LocalizerFor and I18nForLang helpers
- internal/web/controller: trigger reloadDiscordFunc to dynamically reschedule cron upon setting changes
- internal/web/web: register and reschedule DiscordNotifyJob
- tests: comprehensive unit tests for multipart uploads, status reporting, and job execution

* feat(discord): add interactive bot commands via Gateway WebSocket and update documentation

- internal/web/service/discord/gateway: connect to Discord Gateway v10 via WebSocket (gorilla/websocket)
- internal/web/service/discord/gateway: handle heartbeat loop, reconnection, and command dispatch
- commands: implement !status, !report, !backup, !usage <email>, !inbounds, !restart, !help (with ! and / prefixes)
- internal/web/web: start/stop Gateway client with server and reload dynamically on setting updates
- docs: update operations guide (en, ru) with scheduled reports, backups, commands, and privileged intents
- tests: add end-to-end WebSocket Gateway test verifying command handling

* style(discord): fix goimports formatting and add 3x-ui to gitignore

* fix(discord): stop gateway panics, reconnect storms and proxy bypass

The Gateway client wrote to its websocket from both the heartbeat ticker
and the read loop answering server-requested op 1 heartbeats. gorilla
panics on concurrent writes and neither goroutine recovers, so a colliding
heartbeat took the whole panel process down; writes now share writeMu.

It also reconnected every 5s forever after close codes Discord marks
non-reconnectable (4004 bad token, 4010-4014, including 4014 when Message
Content Intent is off), re-identifying and logging a warning each time.
The loop now stops on those codes; the docs say to restart the panel.

The gateway dialed with websocket.DefaultDialer, bypassing the panel
egress proxy the REST client already uses, so where Discord is filtered
notifications arrived but commands never connected.

* fix(discord): deliver the scheduled report when the backup upload fails

SendReport posted the report embed and the x-ui.db/config.json attachments
in one multipart request. Once the database outgrows Discord's upload cap
(20 MiB by default) the request is rejected and the report embed is lost
with it on every run, leaving only a log warning. Send the embed first and
the attachments as a second message.

* chore(discord): delete tests that pass whether or not the code works

TestDiscordNotifyJob_NilServiceNoPanic and TestHandleEvent_NilDiscordService
feed a nil DiscordService that web.go never passes, and
TestDiscordNotifyJob_DisabledNoPanic passes with or without the enable
guard because Xray is not running under test.

* fix(discord): require admin user IDs for bot commands and honor discordLang

Any member who could post in the configured channel could run !backup
(the whole x-ui.db and config.json, even with discordBotBackup off),
!restart and !usage. Commands now run only for the Discord user IDs in
the new discordAdminIds setting; an empty list turns commands off.

discordLang was saved and offered in the UI, but nothing read it, so
every embed stayed English. The test message, alerts, the scheduled
report and command replies now render through I18nForLang in the chosen
language, with a discord section in all 13 locales. InitLocalizer takes
an fs.FS so tests load the real translation files.

---------

Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>

internal/web/translation/pt-BR.json

@@ -1587,8 +1587,31 @@
       "subHappGroupNetwork": "Network & TUN Engine",
       "subHappGroupThemes": "Appearance & Theme",
       "subHappGroupFailover": "Migration & App Management",
-      "subHappGroupAndroid": "Android Per-App Proxy"
-
+      "subHappGroupAndroid": "Android Per-App Proxy",
+      "discordSettings": "Bot do Discord",
+      "discordBotEnable": "Ativar notificações do Discord",
+      "discordBotEnableDesc": "Enviar alertas de sistema e eventos para um canal do Discord via bot",
+      "discordBotToken": "Token do Bot do Discord",
+      "discordBotTokenDesc": "Token do bot do Portal de Desenvolvedores do Discord",
+      "discordTokenConfigured": "O token está configurado. Insira um novo token para substituí-lo.",
+      "discordTokenPlaceholder": "Insira o token do bot",
+      "discordChannelId": "ID do canal",
+      "discordChannelIdDesc": "ID do canal do Discord onde as notificações serão enviadas",
+      "discordAdminIds": "IDs de usuários administradores",
+      "discordAdminIdsDesc": "IDs de usuários do Discord, separados por vírgulas, que podem executar comandos do bot. Mensagens de qualquer outra pessoa são ignoradas e uma lista vazia desativa os comandos.",
+      "discordEventBusNotify": "Notificações do Discord",
+      "testDiscord": "Enviar notificação de teste",
+      "testDiscordDesc": "Enviar uma notificação de teste para verificar o token do bot e o ID do canal",
+      "discordNotInitialized": "Serviço Discord não inicializado",
+      "discordBotNotEnabled": "Bot do Discord não está ativado",
+      "discordTestFailed": "Teste do Discord falhou",
+      "discordTestSuccess": "Notificação de teste enviada com sucesso",
+      "discordBotLanguage": "Idioma do Bot do Discord",
+      "discordNotifyTime": "Hora da Notificação",
+      "discordNotifyTimeDesc": "Com que frequência o bot do Discord envia relatórios periódicos. Escolha um intervalo predefinido ou selecione Personalizado para inserir uma expressão crontab.",
+      "discordNotifyBackup": "Backup do Banco de Dados",
+      "discordNotifyBackupDesc": "Enviar arquivo de backup do banco de dados junto com o relatório.",
+      "discordEventBusNotifyDesc": "Selecione quais eventos disparam notificações no Discord"
     },
     "xray": {
       "importRules": "Importar regras",
@@ -2390,6 +2413,81 @@
       "chooseInbound": "Escolha um Inbound"
     }
   },
+  "discord": {
+    "test": {
+      "title": "Teste de notificação do Discord do 3x-ui",
+      "body": "Esta é uma notificação de teste confirmando que as notificações do Discord estão configuradas corretamente."
+    },
+    "footer": "Painel 3x-ui",
+    "fields": {
+      "panelVersion": "Versão do painel",
+      "xrayCore": "Núcleo Xray",
+      "systemLoad": "Carga do sistema",
+      "networkTraffic": "Tráfego de rede",
+      "totalUsed": "Total usado",
+      "quota": "Cota",
+      "error": "Erro",
+      "delay": "Atraso",
+      "outbound": "Saída",
+      "node": "Nó",
+      "threshold": "Limite",
+      "reason": "Motivo",
+      "time": "Horário",
+      "source": "Origem"
+    },
+    "values": {
+      "uptime": "{{ .Days }}d {{ .Hours }}h",
+      "traffic": "↑{{ .Up }}  ↓{{ .Down }} (Total: {{ .Total }})",
+      "counts": "Total: {{ .Total }} | Esgotando: {{ .Depleting }} | Desativados: {{ .Disabled }}",
+      "inbound": "Protocolo: `{{ .Protocol }}` | Porta: `{{ .Port }}` | Clientes: `{{ .Clients }}` | Tráfego: `↑{{ .Up }} ↓{{ .Down }}` | Estado: `{{ .State }}`"
+    },
+    "alerts": {
+      "outboundDown": "Saída fora do ar",
+      "outboundUp": "Saída restabelecida",
+      "nodeDown": "Nó fora do ar",
+      "nodeUp": "Nó restabelecido",
+      "xrayCrash": "O núcleo Xray travou",
+      "cpuHigh": "Limite de CPU excedido",
+      "memoryHigh": "Limite de memória excedido",
+      "loginSuccess": "Login bem-sucedido",
+      "loginFailed": "Falha no login"
+    },
+    "report": {
+      "title": "📊 Relatório de status do 3x-ui",
+      "summary": "Relatório periódico de status do servidor e do proxy de **{{ .Host }}**",
+      "footer": "Relatório agendado do 3x-ui • Agendamento: {{ .RunTime }}"
+    },
+    "commands": {
+      "helpTitle": "🤖 Comandos do bot do Discord do 3x-ui",
+      "helpDescription": "Comandos disponíveis para monitorar e gerenciar o servidor 3x-ui:",
+      "helpStatus": "Exibe carga do sistema, RAM, CPU, conexões e usuários online",
+      "helpReport": "Gera um relatório de status completo (com backup do BD, se configurado)",
+      "helpBackup": "Envia imediatamente o arquivo de backup do banco de dados",
+      "helpUsage": "Consulta uso de tráfego, cota e validade de um cliente",
+      "helpInbounds": "Lista todas as entradas configuradas com portas e estatísticas de clientes",
+      "helpRestart": "Reinicia o núcleo Xray",
+      "helpHelp": "Exibe esta lista de comandos disponíveis",
+      "statusTitle": "⚡ Status do servidor 3x-ui",
+      "statusDescription": "Métricas operacionais atuais de **{{ .Host }}**",
+      "backupTitle": "🗄️ Backup do banco de dados",
+      "backupDescription": "Arquivo de backup do 3x-ui gerado em `{{ .Time }}`",
+      "backupUnavailable": "❌ Serviço de backup indisponível",
+      "backupFailed": "❌ Falha ao ler o backup do banco de dados: {{ .Error }}",
+      "usageHint": "⚠️ Uso: `!usage <email>` ou `/usage <email>`",
+      "usageTitle": "👤 Uso do cliente: {{ .Email }}",
+      "usageDescription": "Entrada: **{{ .Remark }}** (porta {{ .Port }})",
+      "clientNotFound": "⚠️ O cliente `{{ .Email }}` não foi encontrado em nenhuma entrada configurada.",
+      "inboundsUnavailable": "❌ Serviço de entradas indisponível",
+      "inboundsFailed": "❌ Falha ao carregar as entradas: {{ .Error }}",
+      "inboundsTitle": "🔌 Entradas configuradas",
+      "inboundsDescription": "Total de entradas: **{{ .Count }}**",
+      "noInbounds": "ℹ️ Nenhuma entrada configurada.",
+      "xrayUnavailable": "❌ Serviço do Xray indisponível",
+      "restarting": "🔄 Reiniciando o núcleo Xray...",
+      "restartFailed": "❌ Falha ao reiniciar o Xray: {{ .Error }}",
+      "restartSuccess": "✅ O núcleo Xray foi reiniciado com sucesso."
+    }
+  },
   "email": {
     "labelStatus": "Status",
     "labelOutbound": "Outbound",