feat(project): per-project new-chat defaults (agent, workspace, approval, thinking, model) (#191)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

packages/web/test/draft-cache.test.ts

@@ -11,6 +11,7 @@
 import { describe, expect, it } from "vitest";
 import {
   clearDraft,
+  clearDraftModelRef,
   draftKey,
   loadDraft,
   parseDraft,
@@ -183,6 +184,43 @@ describe("load / save / clear (key isolation, errors silenced)", () => {
     expect(s.map.size).toBe(0);
   });
 
+  it("clearDraftModelRef drops only the model pin, keeping everything else (default-model change follow-through)", () => {
+    // Shared by the models page and the project-settings default-model control: after the
+    // Project default changes, the draft must follow it instead of pinning the old pick.
+    const s = memStorage();
+    saveDraft(
+      draftKey("user-a1", "project-a"),
+      {
+        text: "keep me",
+        agentId: "default_agent",
+        modelRef: { provider: "deepseek", modelId: "deepseek-v4-pro" },
+        skills: ["agent-creation"],
+      },
+      s,
+    );
+    clearDraftModelRef("user-a1", "project-a", s);
+    expect(loadDraft(draftKey("user-a1", "project-a"), s)).toEqual({
+      text: "keep me",
+      agentId: "default_agent",
+      skills: ["agent-creation"],
+    });
+    // No cached pick (or no draft at all): a no-op, never an errant write.
+    clearDraftModelRef("user-a1", "project-a", s);
+    clearDraftModelRef("user-b2", "project-a", s);
+    expect(s.map.has(draftKey("user-b2", "project-a"))).toBe(false);
+    // Scoped by user × Project: another user's pin survives.
+    saveDraft(
+      draftKey("user-b2", "project-a"),
+      { modelRef: { provider: "openai", modelId: "gpt-5" } },
+      s,
+    );
+    clearDraftModelRef("user-a1", "project-a", s);
+    expect(loadDraft(draftKey("user-b2", "project-a"), s).modelRef).toEqual({
+      provider: "openai",
+      modelId: "gpt-5",
+    });
+  });
+
   it("storage throwing (quota/private mode): save does not throw, load yields an empty draft", () => {
     const broken: DraftStorage = {
       getItem: () => {