feat: show who an Azure account signs in as, in Details on its row

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/azure.md

@@ -13,8 +13,17 @@ is listed under each, since their permissions can differ.
 A service principal is used instead when `AZURE_CLIENT_ID`,
 `AZURE_TENANT_ID` and a secret or certificate are set in the environment.
 
-If your az login expires mid-session, the status line says so: press `L` to
-run `az login` without leaving lazysecrets, and everything reloads.
+On an account's group row, the Details pane shows who it signs in as: name,
+user, tenant, object ID, whether the session used MFA, directory roles
+(built-in ones by name) and its subscriptions. It's read from az's account
+list and the token lazysecrets already has, so nothing is fetched for it.
+`y` there copies the object ID, the one access policies and role
+assignments ask for.
+
+If an account's az login has expired, the status line says so once, and the
+Details pane on that account's rows says it until you sign in: press `L`
+there to run `az login` for it without leaving lazysecrets, and everything
+reloads.
 
 ## Permissions