Add component tests for EndRunModal, GameGrid, RulesConfiguration, Layout

33 tests covering rendering, user interactions (userEvent clicks), prop
callbacks, filter state, and conditional description text. Adds a
matchMedia stub to the vitest setup file so components importing
useTheme don't throw in jsdom. Also adds actionlint and zizmor
pre-commit hooks for GitHub Actions linting.

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

prek.toml

@@ -43,5 +43,21 @@ hooks = [
     language = "system",
     files = '^frontend/src/.*\.(ts|tsx)$',
     pass_filenames = false
+  },
+  {
+    id = "actionlint",
+    name = "actionlint",
+    entry = "bash -c 'actionlint'",
+    language = "system",
+    files = '^.github/workflows/.*.(yml|yaml)',
+    pass_filenames = false
+  },
+  {
+    id = "zizmor",
+    name = "zizmor",
+    entry = "bash -c 'zizmor .github/workflows/'",
+    language = "system",
+    files = '^.github/workflows/.*.(yml|yaml)',
+    pass_filenames = false
   }
 ]