refactor: simplify logical expressions and update biome linting rules

biome.json

@@ -20,7 +20,11 @@
       "recommended": true,
       "complexity": {
         "noForEach": "error",
-        "useLiteralKeys": "error"
+        "noUselessFragments": "error",
+        "useLiteralKeys": "error",
+        "noUselessCatch": "error",
+        "useSimplifiedLogicExpression": "error",
+        "noExcessiveCognitiveComplexity": "warn"
       },
       "style": {
         "useConst": "error",

frontend/src/components/ui/ComposeCanvas.tsx

@@ -44,7 +44,7 @@ export const ComposeCanvas = forwardRef<
       };
 
       const finalWidth = await waitForLayout();
-      if (!isMounted || !canvasRef.current || !wrapperRef.current) return;
+      if (!(isMounted && canvasRef.current && wrapperRef.current)) return;
 
       const initialHeight = Math.max(
         wrapperRef.current.clientHeight || 900,
@@ -101,7 +101,7 @@ export const ComposeCanvas = forwardRef<
         canvas.add(textbox);
 
         textbox.on("changed", () => {
-          if (!canvas || !wrapperRef.current) return;
+          if (!(canvas && wrapperRef.current)) return;
           const neededHeight = textbox.top + textbox.height + PAD;
           if (neededHeight > canvas.height) {
             const newH = neededHeight + PAD;

frontend/src/pages/Activate.tsx

@@ -15,7 +15,7 @@ export default function Activate() {
   const navigate = useNavigate();
 
   useEffect(() => {
-    if (!uidb64 || !token || hasCalled.current) return;
+    if (!(uidb64 && token) || hasCalled.current) return;
 
     // prevent double api calls
     hasCalled.current = true;

frontend/src/pages/Editor.tsx

@@ -36,7 +36,7 @@ export default function Editor() {
   const fileInputRef = useRef<HTMLInputElement>(null);
 
   useEffect(() => {
-    if (!public_id || !masterKey) return;
+    if (!(public_id && masterKey)) return;
 
     const loadExistingLetter = async () => {
       setIsInitialLoading(true);
@@ -95,7 +95,7 @@ export default function Editor() {
   };
 
   const handleSave = async (status: "SEALED" | "DRAFT"): Promise<void> => {
-    if (!public_id && !letterIdRef.current) {
+    if (!(public_id || letterIdRef.current)) {
       letterIdRef.current = crypto.randomUUID();
       navigate(PATHS.write(letterIdRef.current), { replace: true });
     } else if (public_id) {