fix(cli): restore KILO env var (regression from #8808)

.changeset/restore-kilo-env-var.md

@@ -0,0 +1,5 @@
+---
+"@kilocode/cli": patch
+---
+
+Restore the `KILO=1` environment variable so plugins and tooling can distinguish the Kilo CLI from upstream OpenCode.

packages/opencode/src/index.ts

@@ -135,7 +135,7 @@ let cli = yargs(args) // kilocode_change
     Heap.start()
 
     process.env.AGENT = "1"
-    process.env.OPENCODE = "1"
+    process.env.KILO = "1"
     process.env.KILO_PID = String(process.pid)
 
     Log.Default.info("opencode", {