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/utils/modelPresets.ts

@@ -0,0 +1,47 @@
+import type { ModelPreset } from "@kb/core";
+
+export function getPresetByName(presets: ModelPreset[], name: string): ModelPreset | undefined {
+  const normalizedName = name.trim().toLowerCase();
+  return presets.find((preset) => preset.name.trim().toLowerCase() === normalizedName);
+}
+
+export function applyPresetToSelection(preset: ModelPreset | undefined): {
+  executorValue: string;
+  validatorValue: string;
+} {
+  return {
+    executorValue: preset?.executorProvider && preset?.executorModelId
+      ? `${preset.executorProvider}/${preset.executorModelId}`
+      : "",
+    validatorValue: preset?.validatorProvider && preset?.validatorModelId
+      ? `${preset.validatorProvider}/${preset.validatorModelId}`
+      : "",
+  };
+}
+
+export function getRecommendedPresetForSize(
+  size: "S" | "M" | "L" | undefined,
+  defaultPresetBySize: Record<string, string>,
+  presets: ModelPreset[],
+): ModelPreset | undefined {
+  if (!size) return undefined;
+  const presetId = defaultPresetBySize[size];
+  if (!presetId) return undefined;
+  return presets.find((preset) => preset.id === presetId);
+}
+
+export function validatePresetId(id: string): boolean {
+  return /^[A-Za-z0-9_-]{1,32}$/.test(id);
+}
+
+export function generatePresetId(name: string): string {
+  const slug = name
+    .trim()
+    .toLowerCase()
+    .replace(/[^a-z0-9_-]+/g, "-")
+    .replace(/-+/g, "-")
+    .replace(/^[-_]+|[-_]+$/g, "")
+    .slice(0, 32);
+
+  return slug || "preset";
+}