fix: resolve 20 Sentry issues and fix navbar test flakiness

Sentry fixes:
- Only send 5xx errors to Sentry (was sending 4xx rate-limit, media type errors)
- Encode non-ASCII chars in X-Output-Filename header (encodeURIComponent)
- Handle FK constraint failures gracefully in file upload, pipeline save, API keys
- Harden getDirSize against ENOENT race on readdirSync

Test fixes:
- Wrap navbar test renders in act() to flush async useEffect state updates
- Add useEffect cleanup to navbar to prevent state updates on unmounted component
- Fixes timeout when running in full test suite

apps/landing/src/components/navbar.tsx

@@ -24,14 +24,18 @@ export function Navbar() {
   const [stars, setStars] = useState<string>("Star");
 
   useEffect(() => {
+    let cancelled = false;
     fetch("https://api.github.com/repos/snapotter-hq/snapotter")
       .then((res) => res.json())
       .then((data) => {
-        if (typeof data.stargazers_count === "number") {
+        if (!cancelled && typeof data.stargazers_count === "number") {
           setStars(formatStarCount(data.stargazers_count));
         }
       })
       .catch(() => {});
+    return () => {
+      cancelled = true;
+    };
   }, []);
 
   return (