docs: explain why proxy TYPE id 25 is reserved (not skipped)

Clarify that TYPE_AWG=26 deliberately skips 25, which is reserved for the
MasterDnsVPN sidecar type on PR #18, so persisted type IDs stay stable when
both branches merge. (Greptile)

Author: hawkff

app/src/main/java/io/nekohasekai/sagernet/database/ProxyEntity.kt

@@ -105,6 +105,10 @@ data class ProxyEntity(
         const val TYPE_ANYTLS = 22
         const val TYPE_JUICITY = 23
         const val TYPE_SNELL = 24
+
+        // 25 is reserved for the MasterDnsVPN sidecar type on the
+        // feature/masterdnsvpn-sidecar branch (PR #18); do not reuse it here so
+        // persisted type IDs stay stable when both branches merge.
         const val TYPE_AWG = 26
 
         const val TYPE_CONFIG = 998