Fix Chrome script injection API detection

[fkuefler]

Summary

This fixes a Chrome runtime failure when submitting through the extension.

Chrome can expose a browser namespace, so checking only typeof browser !== 'undefined' is not a reliable Firefox check. In Chrome, that caused the extension to call browser.tabs.executeScript, which is not available there under Manifest V3, leading to:

TypeError: browser.tabs.executeScript is not a function

What changed

• Use browser.tabs.executeScript only when that specific function exists
• Otherwise fall back to chrome.scripting.executeScript, which is the correct Chrome Manifest V3 path
• Remove the self.chrome = browser shim from the affected files

Files changed

• src/handleSubmit.ts
• src/injectedScript.ts

Verification

• Built the extension with npm run webpack
• Regenerated the unpacked Chrome build with ./create-zip.sh
• Loaded the unpacked extension in Chrome
• Confirmed the previous browser.tabs.executeScript error no longer occurred

[fkuefler]

Really appreciate your fix. Not sure if the original repo owner is ever going to merge your PR, but if he does this fixes a small issue I was having.

[ayaantuts]

Hello @fkuefler
Really appreciate your fix! It works.
I would like to suggest one small change that I noticed:

• CodeForces uses anti-bot verification powered by CloudFlare.
• It takes much longer to verify. Till then, the extension tries to submit the code, leading to the error: Please complete the anti-bot verification.
• It would be great to implement a timeout function or a listener to wait for completion of anti-bot verification?