feat: add App Config detail page with view/edit mode

Click a row in the admin App Config table to navigate to a dedicated
detail page at /admin/appconfig/:appId. Shows all config fields as
badges in view mode; pencil toggles to edit mode with dropdowns.

Traced processors are now editable (capture mode dropdown + remove
button per processor). Sections and header use card styling for
visual contrast. OidcConfigPage gets the same card treatment.

List page simplified to read-only badge overview with row click
navigation.

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

ui/src/pages/Admin/OidcConfigPage.module.css

@@ -11,10 +11,15 @@
 }
 
 .section {
-  margin-bottom: 24px;
+  margin-bottom: 16px;
   display: flex;
   flex-direction: column;
   gap: 12px;
+  background: var(--bg-surface);
+  border: 1px solid var(--border-subtle);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-card);
+  padding: 16px 20px;
 }
 
 .toggleRow {