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/api/src/routes/tools/optimize-for-web.ts

@@ -149,7 +149,7 @@ export function registerOptimizeForWeb(app: FastifyInstance) {
         reply.header("Content-Type", result.contentType);
         reply.header("X-Original-Size", String(fileBuffer.length));
         reply.header("X-Processed-Size", String(result.buffer.length));
-        reply.header("X-Output-Filename", result.filename);
+        reply.header("X-Output-Filename", encodeURIComponent(result.filename));
         return reply.send(result.buffer);
       } catch (err) {
         const message = err instanceof Error ? err.message : "Preview processing failed";