Add QA test outputs, build scripts, and Dockerfile validation

- Created `qa-test-output-after-fix.txt` and `qa-test-output.txt` to log results of certificate page authentication tests.
- Added `build.sh` for deterministic backend builds in CI, utilizing `go list` for efficiency.
- Introduced `codeql_scan.sh` for CodeQL database creation and analysis for Go and JavaScript/TypeScript.
- Implemented `dockerfile_check.sh` to validate Dockerfiles for base image and package manager mismatches.
- Added `sourcery_precommit_wrapper.sh` to facilitate Sourcery CLI usage in pre-commit hooks.

frontend/src/components/ThemeToggle.tsx

@@ -0,0 +1,12 @@
+import { useTheme } from '../hooks/useTheme'
+import { Button } from './ui/Button'
+
+export function ThemeToggle() {
+  const { theme, toggleTheme } = useTheme()
+
+  return (
+    <Button variant="ghost" size="sm" onClick={toggleTheme} title={`Switch to ${theme === 'dark' ? 'light' : 'dark'} mode`}>
+      {theme === 'dark' ? '☀️' : '🌙'}
+    </Button>
+  )
+}