chore: gitignore tsconfig.tsbuildinfo (build cache, not source)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -70,3 +70,6 @@ o6.txt
 o7.txt
 t6.txt
 t7.txt
+
+# TS build cache
+*.tsbuildinfo

packages/casan-control-panel/frontend/tsconfig.tsbuildinfo

@@ -1 +0,0 @@
-{"root":["./src/app.tsx","./src/main.tsx","./src/components/layout/applayout.tsx","./src/components/layout/header.tsx","./src/components/layout/sidebar.tsx","./src/components/ui/card.tsx","./src/lib/api.ts","./src/lib/queryclient.ts","./src/pages/governance.tsx","./src/pages/incidents.tsx","./src/pages/overview.tsx","./src/pages/runs.tsx","./src/pages/security.tsx","./src/pages/traceability.tsx"],"errors":true,"version":"5.9.3"}