feat(KB-184): add model presets for task creation

- Add model preset types and settings fields with API validation
- Create model preset utility helpers for size-based auto-selection
- Add settings UI for managing model presets (create, edit, delete)
- Integrate preset selection into NewTaskModal with custom override option
- Add inline preset selection to InlineCreateCard component
- Persist modelPresetId in task store and preserve through archive/unarchive
- Add changeset and update AGENTS.md with feature documentation

packages/dashboard/app/api.ts

@@ -99,6 +99,7 @@ export function createTask(input: TaskCreateInput): Promise<Task> {
     column,
     dependencies,
     breakIntoSubtasks,
+    modelPresetId,
     modelProvider,
     modelId,
     validatorModelProvider,
@@ -113,6 +114,7 @@ export function createTask(input: TaskCreateInput): Promise<Task> {
       column,
       dependencies,
       breakIntoSubtasks,
+      modelPresetId,
       modelProvider,
       modelId,
       validatorModelProvider,