fix(ssl): strip trailing slash in getBaseUrl + trust OS certificate store for HTTPS streaming

Fixes two bugs reported in #178:

- getBaseUrl() now strips trailing slashes from server URLs, consistent
  with restBaseFromUrl(). A trailing slash caused double-slash stream URLs
  (//rest/stream.view) which Caddy rejects. Trailing slash also caused
  browsing to return 0 results. Fix manually ported from PR #179 by kveld9.

- reqwest now loads the OS native certificate store in addition to
  Mozilla's webpki roots (rustls-tls-native-roots feature). Fixes HTTPS
  streaming failures where the server certificate is signed by a local CA
  (e.g. Caddy internal CA) that is trusted in the system keychain but not
  in Mozilla's root store.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/store/authStore.ts

@@ -546,7 +546,8 @@ export const useAuthStore = create<AuthState>()(
         const s = get();
         const server = s.servers.find(srv => srv.id === s.activeServerId);
         if (!server?.url) return '';
-        return server.url.startsWith('http') ? server.url : `http://${server.url}`;
+        const base = server.url.startsWith('http') ? server.url : `http://${server.url}`;
+        return base.replace(/\/$/, '');
       },
 
       getActiveServer: () => {