feat: add patch size estimation for game updates

- HEAD request to game-patches.hytale.com for content-length
- Track lastPatchId in state to calculate patch delta
- Display formatted size (~55.4 MiB) in update notifications

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

src/modules/hytale-patches/formatter.ts

@@ -1,7 +1,20 @@
 import type { PatchesUpdate } from './tracker.js'
 
+function formatBytes(bytes: number): string {
+  const units = ['B', 'KiB', 'MiB', 'GiB']
+  let size = bytes
+  let unitIndex = 0
+
+  while (size >= 1024 && unitIndex < units.length - 1) {
+    size /= 1024
+    unitIndex++
+  }
+
+  return `${size.toFixed(1)} ${units[unitIndex]}`
+}
+
 export function formatPatchesUpdate(update: PatchesUpdate): string {
-  const { patchline, version, previousVersion, patchId } = update
+  const { patchline, version, previousVersion, patchId, patchSize } = update
   const emoji = patchline === 'release' ? '🎮' : '🧪'
 
   return `<b>${emoji} Hytale Game Patch Update</b>
@@ -9,5 +22,6 @@ export function formatPatchesUpdate(update: PatchesUpdate): string {
 <b>Patchline:</b> <code>${patchline}</code>
 <b>New version:</b> <code>${version}</code>
 ${previousVersion !== 'unknown' ? `<b>Previous:</b> <code>${previousVersion}</code>` : ''}
-${patchId ? `<b>Patch ID:</b> <code>${patchId}</code>` : ''}`
+${patchId ? `<b>Patch ID:</b> <code>${patchId}</code>` : ''}
+${patchSize ? `<b>Size:</b> ~<code>${formatBytes(patchSize)}</code>` : ''}`
 }