feat: extract admin account management rework from PR 124 (#138)

* feat: reorganize admin panel around accounts

* feat: expand admin customer account controls

* feat: add admin account detail management

* fix: remove unused admin account icon import

* refactor: design critique fixes for account pages

- Admin accounts: replace dense card grid with compact DataTable
- Account settings: remove redundant hero card, stat grid, header pills
- Fix bg-accent (orange) misuse on decorative elements across 7 files
- Add ConfirmButton for destructive actions (deactivate, remove member)
- Replace single-field modals with inline editing (plan, trial)
- Add contextual help: display code tooltip, improved empty states
- Non-owner aside explanation for hidden owner-only sections
- Admin sidebar: group 11 items into 5 labeled sections
- Rename UsersPage.tsx → AccountsPage.tsx to match route
- Fix border radius consistency, hide zero-count badges

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

* fix: use get_admin_db for all new admin account endpoints

All admin endpoints query across tenants without a tenant context.
get_db (app-role, subject to RLS) was never imported and would crash
at runtime — replace all 6 occurrences with get_admin_db (BYPASSRLS).

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

---------

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

backend/tests/test_admin.py

@@ -19,8 +19,116 @@ class TestAdminEndpoints:
             "/api/v1/admin/users", headers=admin_auth_headers
         )
         assert response.status_code == 200
-        users = response.json()
-        assert len(users) >= 2  # admin + test_user
+        payload = response.json()
+        assert payload["total"] >= 2  # admin + test_user
+        assert len(payload["items"]) >= 2
+
+    @pytest.mark.asyncio
+    async def test_list_users_supports_search(
+        self, client: AsyncClient, admin_auth_headers: dict, test_user: dict
+    ):
+        """Test admin people search by user email."""
+        response = await client.get(
+            "/api/v1/admin/users",
+            params={"search": test_user["email"]},
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["total"] >= 1
+        assert any(item["email"] == test_user["email"] for item in payload["items"])
+
+    @pytest.mark.asyncio
+    async def test_list_accounts_as_admin(
+        self, client: AsyncClient, admin_auth_headers: dict
+    ):
+        """Test listing accounts with member data."""
+        response = await client.get(
+            "/api/v1/admin/accounts", headers=admin_auth_headers
+        )
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["total"] >= 1
+        assert len(payload["items"]) >= 1
+        assert "members" in payload["items"][0]
+        assert "subscription" in payload["items"][0]
+
+    @pytest.mark.asyncio
+    async def test_create_account_as_admin(
+        self, client: AsyncClient, admin_auth_headers: dict
+    ):
+        """Test creating an empty account from admin."""
+        response = await client.post(
+            "/api/v1/admin/accounts",
+            json={"name": "Acme Customer", "plan": "pro"},
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 201
+        payload = response.json()
+        assert payload["name"] == "Acme Customer"
+        assert payload["subscription"]["plan"] == "pro"
+        assert payload["display_code"]
+
+    @pytest.mark.asyncio
+    async def test_get_account_detail_as_admin(
+        self, client: AsyncClient, admin_auth_headers: dict, test_user: dict
+    ):
+        """Test fetching account detail for management view."""
+        account_id = test_user["user_data"]["account_id"]
+        response = await client.get(
+            f"/api/v1/admin/accounts/{account_id}",
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["id"] == account_id
+        assert "members" in payload
+        assert "invites" in payload
+
+    @pytest.mark.asyncio
+    async def test_update_account_name_as_admin(
+        self, client: AsyncClient, admin_auth_headers: dict, test_user: dict
+    ):
+        """Test renaming an account from admin detail view."""
+        account_id = test_user["user_data"]["account_id"]
+        response = await client.put(
+            f"/api/v1/admin/accounts/{account_id}",
+            json={"name": "Renamed Customer Account"},
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["id"] == account_id
+        assert payload["name"] == "Renamed Customer Account"
+
+    @pytest.mark.asyncio
+    async def test_update_account_plan(
+        self, client: AsyncClient, admin_auth_headers: dict, test_user: dict
+    ):
+        """Test changing an account's subscription plan."""
+        account_id = test_user["user_data"]["account_id"]
+        response = await client.put(
+            f"/api/v1/admin/accounts/{account_id}/subscription/plan",
+            json={"plan": "pro"},
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+        assert response.json()["plan"] == "pro"
+
+    @pytest.mark.asyncio
+    async def test_extend_account_trial(
+        self, client: AsyncClient, admin_auth_headers: dict, test_user: dict
+    ):
+        """Test starting or extending an account trial."""
+        account_id = test_user["user_data"]["account_id"]
+        response = await client.put(
+            f"/api/v1/admin/accounts/{account_id}/subscription/extend-trial",
+            json={"days": 14},
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+        assert response.json()["status"] == "trialing"
+        assert response.json()["current_period_end"] is not None
 
     @pytest.mark.asyncio
     async def test_list_users_as_non_admin(