chore: lint the unstable channel locally too

The local lint task only checked the stable channel while CI checks both,
so a variant-specific lint error could reach the build unnoticed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: malys

mise.toml

@@ -58,7 +58,7 @@ run = './gradlew -Dorg.gradle.java.home=$JAVA_HOME testStableDebugUnitTest testU
 
 [tasks.lint]
 description = "Android lint, stable channel"
-run = './gradlew -Dorg.gradle.java.home=$JAVA_HOME lintStableDebug'
+run = './gradlew -Dorg.gradle.java.home=$JAVA_HOME lintStableDebug lintUnstableDebug'
 
 [tasks.permissions]
 description = "Permission-drift gate (same check the CI runs)"