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/context/ThemeContext.tsx

@@ -0,0 +1,26 @@
+import { useEffect, useState, ReactNode } from 'react'
+import { ThemeContext, Theme } from './ThemeContextValue'
+
+export function ThemeProvider({ children }: { children: ReactNode }) {
+  const [theme, setTheme] = useState<Theme>(() => {
+    const saved = localStorage.getItem('theme')
+    return (saved as Theme) || 'dark'
+  })
+
+  useEffect(() => {
+    const root = window.document.documentElement
+    root.classList.remove('light', 'dark')
+    root.classList.add(theme)
+    localStorage.setItem('theme', theme)
+  }, [theme])
+
+  const toggleTheme = () => {
+    setTheme(prev => prev === 'dark' ? 'light' : 'dark')
+  }
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggleTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  )
+}