fix(ui): hide redundant SSO button in empty state, fix dashboard navigation

- Hide top-right "Add SSO Connection" when no connectors exist (empty
  state already has its own button)
- Fix broken relative navigations on tenant dashboard: ../license and
  ../oidc resolved to wrong paths; now use absolute /tenant/license and
  /tenant/sso

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/tenant/SsoPage.tsx

@@ -185,10 +185,12 @@ export function SsoPage() {
     <div style={{ padding: 24, display: 'flex', flexDirection: 'column', gap: 20 }}>
       <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
         <h1 style={{ margin: 0, fontSize: '1.25rem', fontWeight: 600 }}>Enterprise SSO</h1>
-        <Button variant="primary" onClick={() => setShowCreate((v) => !v)}>
-          <Plus size={16} style={{ marginRight: 6, verticalAlign: -3 }} />
-          Add SSO Connection
-        </Button>
+        {connectors && connectors.length > 0 && (
+          <Button variant="primary" onClick={() => setShowCreate((v) => !v)}>
+            <Plus size={16} style={{ marginRight: 6, verticalAlign: -3 }} />
+            Add SSO Connection
+          </Button>
+        )}
       </div>
 
       {showCreate && (

ui/src/pages/tenant/TenantDashboardPage.tsx

@@ -155,11 +155,11 @@ export function TenantDashboardPage() {
                 Open Server Dashboard
               </Button>
             )}
-            <Button variant="secondary" onClick={() => navigate('../license')}>
+            <Button variant="secondary" onClick={() => navigate('/tenant/license')}>
               <Key size={14} style={{ marginRight: 6, verticalAlign: -2 }} />
               View License
             </Button>
-            <Button variant="secondary" onClick={() => navigate('../oidc')}>
+            <Button variant="secondary" onClick={() => navigate('/tenant/sso')}>
               <Settings size={14} style={{ marginRight: 6, verticalAlign: -2 }} />
               Configure OIDC
             </Button>