Fix async/await syntax error and remove unused config.js reference

[Copilot]

Post-merge issues from PR #60: handleRxLogEvent used await without async declaration, and index.html referenced non-existent config.js.

Changes

• wardrive.js: Added async to handleRxLogEvent function declaration
• index.html: Removed <script src="content/config.js"></script> reference

// Before
function handleRxLogEvent(data, originalPayload, channelIdx, expectedChannelHash) {
  const decryptedMessage = await decryptGroupTextPayload(...);  // SyntaxError
}

// After
async function handleRxLogEvent(data, originalPayload, channelIdx, expectedChannelHash) {
  const decryptedMessage = await decryptGroupTextPayload(...);
}

Original prompt

I got error

Uncaught SyntaxError: Unexpected reserved word (at wardrive.js:1239:32)

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