feat: add testing framework and initial test cases

- Updated package.json to include Vitest and testing dependencies.
- Created test cases for SuitePicker component to validate selection logic.
- Added tests for ReportsPage to ensure correct report grouping and ordering.
- Implemented read-only enforcement tests for SuitePage to prevent actions on built-in suites.
- Introduced a setup file for Vitest to include jest-dom matchers and cleanup after tests.
- Modified ReportsPage to group reports by model and display them accordingly.
- Enhanced API types to include suite_scope and question_count for better report handling.

web/src/lib/api.ts

@@ -186,6 +186,10 @@ export interface ReportSummary {
   model_label: string
   size_bytes: number
   modified_at: number
+  /** Which suites the run covered. Empty for reports predating the scheme. */
+  suite_scope: string
+  /** How many questions it actually ran. Null for legacy reports. */
+  question_count: number | null
 }
 
 export interface ReportDetail extends ReportSummary {

web/src/lib/router.tsx

@@ -3,7 +3,8 @@
  *
  * The app has five top-level views and no data loaders, so a routing library
  * would be pure overhead. This gives real URLs, working back/forward buttons
- * and deep links (e.g. /reports/automated_report_Qwen.md) with no dependency.
+ * and deep links (e.g. /reports/Qwen3.5-9B__20260728-0318__all__26q.md) with
+ * no dependency.
  */
 
 import {