Add "maintained by SIPB" badge (#80)

It was suggested a while back that we add a "maintained by SIPB" badge
to Hydrant; of course, this is all the more relevant now that the spring
2025 listings are up and lots of people are using Hydrant.

This is modelled after the DormSoup project:
https://github.com/DormSoup/dormsoup/blob/main/app/components/SIPBLogo.tsx

src/components/App.tsx

@@ -32,6 +32,7 @@ import "./App.scss";
 import { MatrixLink } from "./MatrixLink";
 import { useICSExport } from "../lib/gapi";
 import { CalendarIcon } from "@chakra-ui/icons";
+import { SIPBLogo } from "./SIPBLogo";
 
 type SemesterData = {
   classes: { [cls: string]: RawClass };
@@ -96,7 +97,7 @@ function useHydrant(): {
 /**
  * "Integration callbacks" allow other SIPB projects to integrate with Hydrant by redirecting to
  * https://hydrant.mit.edu/#/export with a `callback` as a query parameter.
- * 
+ *
  * Currently, the only application that uses this is the Matrix class group chat picker,
  * but in the future, a prompt "[Application name] would like to access your Hydrant class list"
  * could be implemented.
@@ -120,7 +121,7 @@ function HydrantApp() {
   useEffect(() => {
     // only trigger this code if the URL asked for it
     if (!hasIntegrationCallback) return;
-    
+
     // wait until Hydrant loads
     if (!hydrant) return;
 
@@ -205,6 +206,7 @@ function HydrantApp() {
                   </Button>
                 </Tooltip>
                 <MatrixLink selectedActivities={state.selectedActivities}/>
+                <SIPBLogo/>
               </HStack>
             </Center>
             <SelectedActivities

src/components/SIPBLogo.tsx

@@ -0,0 +1,25 @@
+import { Button, Image } from "@chakra-ui/react";
+
+export function SIPBLogo() {
+  return (
+    <a
+      href="https://sipb.mit.edu/"
+      target="_blank"
+      rel="noreferrer"
+    >
+      <Button
+        colorScheme="gray"
+        rightIcon={
+          <Image
+            src="/fuzzball.png"
+            alt="SIPB Logo"
+            height={6}
+          />
+        }
+        size="sm"
+      >
+        Maintained by SIPB
+      </Button>
+    </a>
+  );
+}