Fix bug

When the user clicks a project on /projects, and then clicks
"New task" the project that has been clicked should persist to
the "New task" page.

client/src/js/components/App.tsx

@@ -16,6 +16,14 @@ export function App({ children }: PropsWithChildren<{}>) {
   const cookies = Object.fromEntries(
     document.cookie.split(";").map(e => e.split("=")),
   );
+  /* allowlist: param keys acceptable as cookie keys */
+  const allowlist = ["projectId"];
+  Object.entries(params).forEach(([key, value]) => {
+    if (allowlist.includes(key) && cookies[key] !== value &&
+        /^[0-9A-Za-z]+$/.test(String(value))) {
+      document.cookie = `${key}=${value}; path=/`;
+    }
+  });
   return (
     <AppContext.Provider value={{ params, cookies }}>
       <ApolloProvider client={client}>{children}</ApolloProvider>