fix: add text reporter to vitest so coverage script can parse frontend coverage

The coverage script parses "All files" from vitest text table output, but
vitest was only configured with json-summary reporter. This caused frontend
coverage to show as 0%, pulling overall coverage below threshold.

Frontend line coverage is 68.4%, making overall coverage 66.4% vs 64.60% threshold.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.coverage_baseline

@@ -1 +1 @@
-64.60
+66.4

frontend/vitest.config.ts

@@ -11,7 +11,7 @@ export default defineConfig({
     exclude: ["tests/e2e/**", "node_modules/**"],
     coverage: {
       provider: "v8",
-      reporter: ["json-summary"],
+      reporter: ["text", "json-summary"],
       reportsDirectory: "./coverage",
     },
   },