Migrate to TypeScript (#1)

* rf: js -> ts

* [m] docs: add badges, lint

spamwatch.ts

@@ -0,0 +1,28 @@
+import fs from 'fs';
+import path from 'path';
+
+const blocklistPath = path.join(__dirname, 'sw_blocklist.txt');
+
+let blocklist: string[] = [];
+
+const readBlocklist = () => {
+  try {
+    const data = fs.readFileSync(blocklistPath, 'utf8');
+    blocklist = data.split('\n').map(id => id.trim()).filter(id => id !== '');
+  } catch (error) {
+    if (error.code === 'ENOENT') {
+      console.log('WARN: SpamWatch blocklist file not found. Creating a new, blank one.\nUse your own SpamWatch API key and our generator to push the blocklist to the file.');
+      fs.writeFileSync(blocklistPath, '');
+    } else {
+      console.error('WARN: Error reading SpamWatch blocklist:', error);
+    }
+  }
+};
+
+const isOnSpamWatch = (userId: string) => {
+  return blocklist.includes(userId);
+};
+
+readBlocklist();
+
+export { isOnSpamWatch };