feat: pin sessions to workspace revisions

backend/test/routes-settings.test.ts

@@ -31,8 +31,8 @@ test("GET /settings returns effective defaults (env provider/model/thinking, fir
   }
 });
 
-test("PUT /settings persists and GET reads it back", async () => {
-  const { app, dir } = appWithTmpSettings({}, {
+test("PUT /settings does not persist personal workspace or LLM choices", async () => {
+  const { app, dir } = appWithTmpSettings({ PI_PROVIDER: "zai", PI_MODEL: "glm-5.2", PI_THINKING: "medium" }, {
     listModels: async () => [{ provider: "zai", id: "glm-5.2", name: "GLM 5.2", reasoning: true }],
   });
   try {
@@ -42,13 +42,14 @@ test("PUT /settings persists and GET reads it back", async () => {
     });
     expect(put.statusCode).toBe(200);
     const got = await app.inject({ method: "GET", url: "/settings" });
-    expect(got.json()).toMatchObject({ workspace: "psd", provider: "zai", model: "glm-5.2", thinking: "high" });
+    expect(got.json()).toMatchObject({ provider: "zai", model: "glm-5.2", thinking: "medium" });
+    expect(got.json()).not.toMatchObject({ workspace: "psd", thinking: "high" });
   } finally {
     rmSync(dir, { recursive: true, force: true });
   }
 });
 
-test("settings are isolated by the authenticated repository principal", async () => {
+test("settings no longer read or write principal-specific preferences", async () => {
   const preferences = new Map<string, any>();
   const runner = {
     withPrincipal: (principal: any) => ({
@@ -73,11 +74,11 @@ test("settings are isolated by the authenticated repository principal", async ()
   const alice = await app.inject({ method: "GET", url: "/settings", headers: headers("alice") });
   const bob = await app.inject({ method: "GET", url: "/settings", headers: headers("bob") });
 
-  expect(alice.json()).toMatchObject({ workspace: "psd", thinking: "high" });
-  expect(bob.json()).not.toMatchObject({ workspace: "psd", thinking: "high" });
+  expect(alice.json()).toEqual(bob.json());
+  expect(preferences.size).toBe(0);
 });
 
-test("GET /settings seeds an empty private profile from complete legacy settings once", async () => {
+test("GET /settings retains complete legacy installation defaults without seeding a private profile", async () => {
   let preferences: Record<string, unknown> = {};
   const writes: Record<string, unknown>[] = [];
   const runner = {
@@ -104,13 +105,13 @@ test("GET /settings seeds an empty private profile from complete legacy settings
     expect(first.statusCode).toBe(200);
     expect(first.json()).toEqual(expected);
     expect(second.json()).toEqual(expected);
-    expect(writes).toEqual([expected]);
+    expect(writes).toEqual([]);
   } finally {
     rmSync(dir, { recursive: true, force: true });
   }
 });
 
-test("GET /settings does not overwrite an existing private profile with legacy settings", async () => {
+test("GET /settings ignores stale private preferences in favor of installation defaults", async () => {
   const privateSettings = {
     workspace: "private", provider: "zai", model: "glm-5.2", thinking: "high",
   };
@@ -130,7 +131,9 @@ test("GET /settings does not overwrite an existing private profile with legacy s
     const response = await app.inject({ method: "GET", url: "/settings" });
 
     expect(response.statusCode).toBe(200);
-    expect(response.json()).toEqual(privateSettings);
+    expect(response.json()).toEqual({
+      workspace: "local", provider: "local-qwen", model: "qwen3.6-35b-a3b", thinking: "low",
+    });
   } finally {
     rmSync(dir, { recursive: true, force: true });
   }