refactor: convert to modular system with Hytale update trackers

- Core infrastructure: module interface, Telegram wrapper, OAuth token manager, state store
- Migrate Discord forwarder to modules/discord-forwarder/
- Add Hytale update trackers: launcher, patches, downloader, server
- Support multiple Telegram chats with per-chat topic IDs
- Unified config with legacy migration and env var fallbacks
- Auto-refresh OAuth tokens (5min buffer)

Co-Authored-By: Claude <noreply@anthropic.com>

src/modules/hytale-launcher/index.ts

@@ -0,0 +1,73 @@
+import type { Module, ModuleDependencies } from '../../core/module.js'
+import type { HytaleTrackerConfig } from '../../types.js'
+import { formatLauncherUpdate } from './formatter.js'
+import { checkLauncherUpdate } from './tracker.js'
+
+export function hytaleLauncherFactory(
+  moduleConfig: unknown,
+  deps: ModuleDependencies,
+): Module {
+  const config = moduleConfig as HytaleTrackerConfig
+
+  class HytaleLauncherModule implements Module {
+    readonly name = 'hytale-launcher'
+    private dependencies: ModuleDependencies
+    private config: HytaleTrackerConfig
+    private running = false
+    private intervalId: NodeJS.Timeout | null = null
+
+    constructor(cfg: HytaleTrackerConfig, deps: ModuleDependencies) {
+      this.config = cfg
+      this.dependencies = deps
+    }
+
+    isRunning(): boolean {
+      return this.running
+    }
+
+    async start(): Promise<void> {
+      if (this.running)
+        return
+
+      this.dependencies.logger(this.name, `Starting (poll interval: ${this.config.pollIntervalMinutes}min)`)
+
+      // Initial check
+      await this.check()
+
+      // Start polling
+      this.intervalId = setInterval(() => {
+        this.check().catch((err) => {
+          this.dependencies.logger(this.name, `Check failed: ${err}`)
+        })
+      }, this.config.pollIntervalMinutes * 60 * 1000)
+
+      this.running = true
+    }
+
+    async stop(): Promise<void> {
+      if (!this.running)
+        return
+
+      if (this.intervalId) {
+        clearInterval(this.intervalId)
+        this.intervalId = null
+      }
+      this.running = false
+    }
+
+    private async check(): Promise<void> {
+      const update = await checkLauncherUpdate(this.dependencies.stateStore)
+      if (update) {
+        const message = formatLauncherUpdate(update)
+        await this.dependencies.telegram.sendMessage({
+          text: message,
+          chatIds: this.config.chatIds,
+          disableLinkPreview: true,
+        })
+        this.dependencies.logger(this.name, `Update detected: ${update.version}`)
+      }
+    }
+  }
+
+  return new HytaleLauncherModule(config, deps)
+}