[aidan] feat/scheduled-tasks: calendar, rename, and edit workflows (#94)

* [aidan] bug: fix schedule button

* [aidan] fix/agent-errors: surface provider rate limits

* [aidan] ux/cards: click-to-rename for chat and workflow titles

Single-click a card's title to enter edit mode inline. Commit on Enter/blur,
cancel on Escape. Rename persists via PATCH for workflows and sessions.

* [aidan] feat/workflows: seed build prompt for zero-step workflows

When a new workflow has no steps, seed the agent with a prompt asking
the user to describe what the workflow should do, rather than starting blank.

* [aidan] feat/workflows: add-to-schedule popover for unscheduled workflows

Clicking the "+" on an unscheduled workflow row opens a popover with two options:
- Keep this schedule: enables the workflow's existing cadence and moves it to Scheduled
- Change schedule: opens the scheduling editor to pick a different time

* [aidan] ux/workflows: wire add-to-schedule popover and simplify New button

- Made the "+" icon on unscheduled workflow rows clickable, opening a popover
  to keep or change the schedule
- Removed AddIcon from toolbar "New" button (now reads "New" instead of "+ New")

* [aidan] fix/scheduled-tasks: open schedule calendar when Schedule pill clicked

Fixed the Schedule pill click being swallowed by the toolbar's dismiss handler.
Exempted the toolbar pills via data-toolbar-pills so their click handlers fire.

* [aidan] ux/workflows: open New workflow in agent build chat instead of empty card

When creating a new workflow from the hub, open it in edit_agent view (with the
agent builder chat) instead of a preview card. The workflow is created on the
backend first so the embedded session has a real ID.

frontend/src/app/components/editor/useDomElementSelector.ts

@@ -6,7 +6,7 @@ const SELECT_ATTR = 'data-select-type';
 const SELECT_ID_ATTR = 'data-select-id';
 const SELECT_META_ATTR = 'data-select-meta';
 
-const DRAG_SELECT_TYPES = ['agent-card', 'view-card', 'browser-card'] as const;
+const DRAG_SELECT_TYPES = ['agent-card', 'view-card', 'browser-card', 'workflow-card', 'workflows-hub-card'] as const;
 const DRAG_SELECTOR = DRAG_SELECT_TYPES.map((t) => `[${SELECT_ATTR}="${t}"]`).join(',');
 
 export interface OverlayState {
@@ -38,6 +38,8 @@ const SEMANTIC_LABELS: Record<string, string> = {
   'tool-group': 'Tool Group',
   'view-card': 'View',
   'browser-card': 'Browser',
+  'workflow-card': 'Workflow',
+  'workflows-hub-card': 'Workflows',
 };
 
 function findSelectableAncestor(target: Element, excludeId?: string | null): Element | null {