T24a round 1 fix

- overlays::Dialog caps its card at the window, a title bar's height clear
  at each end, and scrolls its body while heading and actions stay; the
  fullscreen body scrolls too; test a_tall_dialog_keeps_its_actions_in_the_window
- ToolCallCard's tool name gives way with an Ellipsis, so time and chevron
  stay in a narrow column; the gallery shows one at 280px
- the Agent script shuts the card it opened, so each theme's shot opens it
- AGENTS: dialogs fit the window

TASKS.md

@@ -272,3 +272,4 @@ Per-component lines live in `tasks/`. Tags there:
 | T23d | 1 | FAIL | the list grouped days in a silent UTC fallback when the system zone was unknown; Combobox and MultiSelect opened a long list at its top, away from the choice |
 | T23d | 2 | PASS | |
 | T23e | 1 | PASS | |
+| T24a | 1 | FAIL | tall arguments pushed the approval dialog's title and buttons off screen; a long tool name in a narrow column pushed the time and chevron out of the card; the dark capture closed the card the light one opened |