feat(ui): add follow button, follows card, and inbox page

src/pages/PublicProfilePage.test.jsx

@@ -25,6 +25,7 @@ function mockBackends({name = 'Lobo', profileStatus = 200, libraryStatus = 200,
         ...(me && {
             'GET /api/users/me': json(200, me),
             'PUT /api/users/settings/profile-tiles': json(204, {}),
+            'GET /api/follows': json(200, {following: [], followers: []}),
         }),
     });
 }
@@ -238,6 +239,34 @@ describe('PublicProfilePage', () => {
         }
     });
 
+    it('offers "Follow" to a logged-in visitor, not to the owner and not to a guest', async () => {
+        localStorage.setItem('tbp_session', '1');
+        try {
+            mockBackends({me: {displayName: 'Someone', role: 'USER'}});
+            const visitor = renderPage();
+            expect(await screen.findByRole('button', {name: 'FOLLOW.FOLLOW'})).toBeTruthy();
+            visitor.unmount();
+
+            mockBackends({me: {displayName: 'Lobo', role: 'USER'}});
+            renderPage();
+            await screen.findByRole('button', {name: 'TILES.CUSTOMIZE'});
+            expect(screen.queryByRole('button', {name: 'FOLLOW.FOLLOW'})).toBeNull();
+            expect(fetch).not.toHaveBeenCalledWith(expect.stringContaining('/api/follows'), expect.anything());
+        } finally {
+            localStorage.clear();
+        }
+    });
+
+    it('offers no "Follow" to a guest', async () => {
+        mockBackends();
+        renderPage();
+
+        await screen.findByText('Portal 2');
+
+        expect(screen.queryByRole('button', {name: 'FOLLOW.FOLLOW'})).toBeNull();
+        expect(fetch).not.toHaveBeenCalledWith(expect.stringContaining('/api/follows'), expect.anything());
+    });
+
     it('shows no "Customize" to a visitor', async () => {
         localStorage.setItem('tbp_session', '1');
         try {