feat(01-01): add iOS Kotlin/Native binary flags to gradle.properties

- kotlin.native.binary.gc=cms (concurrent mark-sweep collector)
- kotlin.native.binary.objcDisposeOnMain=false (off-main-thread
  Obj-C deinit) — avoids UI-thread pause spikes in CMP on iOS
- Enforces INFRA-03 / D-18 / CLAUDE.md convention #7 /
  PITFALLS.md #1 on day 1 before any iOS code is compiled

gradle.properties

@@ -8,3 +8,8 @@ org.gradle.caching=true
 #Android
 android.nonTransitiveRClass=true
 android.useAndroidX=true
+
+# Kotlin/Native iOS (PITFALLS.md #1; D-18; INFRA-03) — MANDATORY day 1
+# CMS GC + non-main-thread Obj-C deinit to avoid UI-thread pause spikes in Compose Multiplatform.
+kotlin.native.binary.gc=cms
+kotlin.native.binary.objcDisposeOnMain=false