Release 0.1: Complete BinectChrome implementation

Implements all requirements from ProductRequirementsDocument.md:
- PDF detection via Chrome Downloads API
- Secure credential storage with AES-GCM encryption
- Binect API integration for PDF uploads
- Popup UI with Binect branding
- Local transfer tracking (500 entry cap)
- Help page with tracking view and CSV export
- 60-day credential retention with auto-expiry
- Accessibility compliance (WCAG 2.1 AA)

Technical implementation:
- Chrome Extension Manifest V3
- TypeScript with strict mode
- Webpack build system
- Jest test suite (22/22 passing)
- ESLint configured (0 errors)

Build output: 13 KB total (production minified)
Test coverage: crypto, pdf-detector, tracker, binect-api

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/background/service-worker.ts

@@ -0,0 +1,101 @@
+/**
+ * Service Worker (Background Script)
+ * Handles PDF detection and credential expiry checks
+ */
+
+import { startPDFDetection, DetectedPDF } from '../utils/pdf-detector';
+import { loadCredentials } from '../utils/storage';
+
+// Store last detected PDF in memory (ephemeral)
+let lastDetectedPDF: DetectedPDF | null = null;
+
+/**
+ * Initialize extension on install
+ */
+chrome.runtime.onInstalled.addListener((details) => {
+  if (details.reason === 'install') {
+    console.log('BinectChrome installed');
+    setupCredentialExpiryAlarm();
+  } else if (details.reason === 'update') {
+    console.log('BinectChrome updated');
+  }
+});
+
+/**
+ * Handle extension startup
+ */
+chrome.runtime.onStartup.addListener(() => {
+  console.log('BinectChrome started');
+  setupCredentialExpiryAlarm();
+});
+
+/**
+ * Set up alarm to check credential expiry daily
+ */
+function setupCredentialExpiryAlarm() {
+  chrome.alarms.create('checkCredentialExpiry', {
+    delayInMinutes: 1, // First check in 1 minute
+    periodInMinutes: 24 * 60 // Then every 24 hours
+  });
+}
+
+/**
+ * Handle alarm events
+ */
+chrome.alarms.onAlarm.addListener((alarm) => {
+  if (alarm.name === 'checkCredentialExpiry') {
+    checkAndDeleteExpiredCredentials();
+  }
+});
+
+/**
+ * Check if credentials are expired and delete them
+ */
+async function checkAndDeleteExpiredCredentials() {
+  const credentials = await loadCredentials();
+  // loadCredentials already handles expiry check and deletion
+  // If credentials are expired, it returns null and deletes them
+  if (credentials === null) {
+    console.log('Credentials expired and deleted');
+  }
+}
+
+/**
+ * Start PDF detection
+ */
+startPDFDetection((pdf: DetectedPDF) => {
+  console.log('PDF detected:', pdf.filename);
+  lastDetectedPDF = pdf;
+
+  // Update badge to indicate PDF detected
+  chrome.action.setBadgeText({ text: '1' });
+  chrome.action.setBadgeBackgroundColor({ color: '#4A90E2' }); // Binect Blue
+});
+
+/**
+ * Handle messages from popup
+ */
+chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
+  if (request.action === 'getLastPDF') {
+    sendResponse({ pdf: lastDetectedPDF });
+    return true;
+  }
+
+  if (request.action === 'clearLastPDF') {
+    lastDetectedPDF = null;
+    chrome.action.setBadgeText({ text: '' });
+    sendResponse({ success: true });
+    return true;
+  }
+
+  if (request.action === 'pdfSent') {
+    // Clear badge after successful send
+    chrome.action.setBadgeText({ text: '' });
+    sendResponse({ success: true });
+    return true;
+  }
+
+  return false;
+});
+
+console.log('BinectChrome service worker loaded');