Cleanup: AUTH_HEADERS pattern duplicated across 5 frontend files

[gkorland]

Description

The AUTH_HEADERS pattern is copy-pasted across 5 frontend files:

• app/src/App.tsx
• app/src/components/Input.tsx
• app/src/components/chat.tsx
• app/src/components/code-graph.tsx
• app/src/components/combobox.tsx

Each contains:

const AUTH_HEADERS: HeadersInit = import.meta.env.VITE_SECRET_TOKEN
  ? { 'Authorization': \`Bearer \${import.meta.env.VITE_SECRET_TOKEN}\` }
  : {};

Suggested Fix

Extract to a shared utility:

// app/src/lib/auth.ts
export const AUTH_HEADERS: HeadersInit = import.meta.env.VITE_SECRET_TOKEN
  ? { 'Authorization': \`Bearer \${import.meta.env.VITE_SECRET_TOKEN}\` }
  : {};

Then import from each file.

Context

Found during code review of PR #522.