chore: pre-release cleanup

- Remove dead chatgpt.js (unused — all auth flows go through signup-page.js)
- Remove chatgpt.com from manifest content_scripts
- Fix resetState() to preserve vpsUrl and mailProvider on manual reset
- Add 30s timeout to all tabs.onUpdated listeners (prevent hanging)
- Fix misleading "All runs finished" log when loop breaks early
- Remove stale TODO comment in signup-page.js
- Add disabled styles for .btn-primary and .run-count-input
- Remove unused `indicator` variable in sidepanel.js
- Fix trailing comma in manifest.json

content/signup-page.js

@@ -40,7 +40,6 @@ async function handleCommand(message) {
 async function step2_clickRegister() {
   log('Step 2: Looking for Register/Sign up button...');
 
-  // TODO: Adjust selectors based on actual OpenAI auth page
   let registerBtn = null;
   try {
     registerBtn = await waitForElementByText(