refactor(mobile): extract shared MIME type utility and improve error handling

- Extract EXT_TO_MIME map and mimeTypeFromFilename to shared module
  at mobile/src/utils/mimeTypes.ts (used by _layout.tsx and +not-found.tsx)
- Add error logging to ensureLocalUri catch block for debugging
- Add error handling to Linking.openURL calls in ProfileScreen
- Fix incorrect LSSupportsOpeningDocumentsInPlace docs in audit report

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

mobile/src/screens/UploadScreen.tsx

@@ -95,8 +95,9 @@ export default function UploadScreen() {
     try {
       await FileSystem.copyAsync({ from: uri, to: destUri });
       return destUri;
-    } catch {
+    } catch (copyErr) {
       // Copy failed – fall back to the original URI (might work for some paths).
+      console.warn("[ensureLocalUri] copyAsync failed:", { from: uri, to: destUri, error: copyErr });
       return uri;
     }
   }, []);