chore(lint): enforce 2-space indent & add gpg pre-commit hook

src/style.css

@@ -212,6 +212,12 @@ body {
   box-sizing: border-box;
 }
 
+::placeholder {
+  color: var(--text-muted);
+  opacity: 1;
+  /* Override Firefox default opacity */
+}
+
 .tool-textarea {
   font-family: monospace;
   resize: none;