feat(02-05): admin tab components and AdminView

- AdminView.vue: tabbed layout (Users | Quotas | AI Config) with UI-SPEC tab strip classes
- AdminUsersTab.vue: user table with create form (crypto.getRandomValues password), inline deactivation confirmation, reactivate, reset-password, row-level spinner, empty state
- AdminQuotasTab.vue: quota inline edit with MB display, usage %, warning when limit < usage
- AdminAiConfigTab.vue: AI provider/model per-user with 1.5s "Saved" confirmation
- client.js: fix adminDeactivateUser/adminReactivateUser to use PATCH /status endpoint, fix adminResetUserPassword to /password-reset, fix adminUpdateAiConfig to send ai_provider/ai_model, add adminGetUserQuota
- No impersonation UI in any admin component (T-02-31)

frontend/src/api/client.js

@@ -225,15 +225,27 @@ export function adminCreateUser(body) {
 }
 
 export function adminDeactivateUser(id) {
-  return request(`/api/admin/users/${id}/deactivate`, { method: 'POST' })
+  return request(`/api/admin/users/${id}/status`, {
+    method: 'PATCH',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ is_active: false }),
+  })
 }
 
 export function adminReactivateUser(id) {
-  return request(`/api/admin/users/${id}/reactivate`, { method: 'POST' })
+  return request(`/api/admin/users/${id}/status`, {
+    method: 'PATCH',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ is_active: true }),
+  })
 }
 
 export function adminResetUserPassword(id) {
-  return request(`/api/admin/users/${id}/reset-password`, { method: 'POST' })
+  return request(`/api/admin/users/${id}/password-reset`, { method: 'POST' })
+}
+
+export function adminGetUserQuota(id) {
+  return request(`/api/admin/users/${id}/quota`)
 }
 
 export function adminUpdateQuota(id, limitBytes) {
@@ -248,6 +260,6 @@ export function adminUpdateAiConfig(id, provider, model) {
   return request(`/api/admin/users/${id}/ai-config`, {
     method: 'PATCH',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ provider, model }),
+    body: JSON.stringify({ ai_provider: provider, ai_model: model }),
   })
 }