feat: add provider-aware browser QA setup

Detect host-native browser tools before offering the isolated local Chromium fallback, add a common readiness fixture, harden managed browser startup, and verify standards installs expose one canonical QA skill.

scripts/gstack2/test-install-matrix.ts

@@ -39,6 +39,12 @@ export const AGENT_MATRIX: readonly AgentMatrixEntry[] = [
     projectPath: ['.agents', 'skills'],
     globalPath: ['.agents', 'skills'],
   },
+  {
+    agent: 'kimi-code-cli',
+    label: 'Kimi Code CLI',
+    projectPath: ['.agents', 'skills'],
+    globalPath: ['.agents', 'skills'],
+  },
   {
     agent: 'cursor',
     label: 'Cursor',