fix(desktop): macOS updates relaunch the app even when its label changes

docs/operations/connect-setup.md

@@ -119,15 +119,15 @@ actual web and server ports. For example, with the default ports:
 ```sh
 VITE_DEV_SERVER_URL=http://127.0.0.1:5733 \
 T3CODE_PORT=13773 \
-  "/Applications/T3 Code (Alpha).app/Contents/MacOS/T3 Code (Alpha)"
+  "/Applications/T3 Code (Beta).app/Contents/MacOS/T3 Code (Beta)"
 ```
 
 Rebuild the signed app after native dependency, main-process, preload, entitlement, provisioning,
 or signing changes. Renderer edits can reuse it. Verify the installed bundle before testing:
 
 ```sh
-codesign --verify --deep --strict "/Applications/T3 Code (Alpha).app"
-codesign -d --entitlements :- "/Applications/T3 Code (Alpha).app"
+codesign --verify --deep --strict "/Applications/T3 Code (Beta).app"
+codesign -d --entitlements :- "/Applications/T3 Code (Beta).app"
 ```
 
 ## Restricting sign-ups

docs/operations/release.md

@@ -7,7 +7,13 @@ This document covers the unified release workflow for stable and nightly desktop
 Beta is the product label, not a release channel or version suffix. Release channels
 remain stable and nightly. To ship 0.1.0 Beta, use `channel=stable` and
 `version=0.1.0`. Removing the Beta label later is a branding change independent of
-the version.
+the version. Keep the macOS executable name `T3 Code (Beta)` unchanged so
+Squirrel.Mac can relaunch after label or channel changes. The nightly DMG still
+installs as `T3 Code (Nightly).app`, beside stable, so the `t3-code@nightly`
+Homebrew cask needs no change. One exception, for the first nightly with this name: a
+nightly installed before it, with no stable app beside it, moves to `T3 Code (Beta).app`
+and doesn't relaunch, leaving the cask's app missing. Say so in that nightly's notes:
+`brew reinstall --cask t3-code@nightly`, then delete the moved `T3 Code (Beta).app`.
 
 ## What the workflow does
 

scripts/build-desktop-artifact.test.ts

@@ -503,6 +503,45 @@ it.layer(NodeServices.layer)("build-desktop-artifact", (it) => {
     }),
   );
 
+  it.effect("keeps the macOS bundle filename stable across product names", () =>
+    Effect.gen(function* () {
+      const stable = yield* createBuildConfig(
+        "mac",
+        "dmg",
+        "0.1.0",
+        false,
+        false,
+        undefined,
+        undefined,
+      );
+      const nightly = yield* createBuildConfig(
+        "mac",
+        "dmg",
+        "0.1.1-nightly.20261017.3238",
+        false,
+        false,
+        undefined,
+        undefined,
+      );
+
+      // Existing installs live at this path; changing it fails their relaunch.
+      assert.notEqual(stable.productName, nightly.productName);
+      assert.equal((stable.mac as { executableName: string }).executableName, "T3 Code (Beta)");
+      assert.equal((nightly.mac as { executableName: string }).executableName, "T3 Code (Beta)");
+      // A fresh nightly install must not land on, and replace, the stable app.
+      const dmgAppName = (config: typeof stable) =>
+        (config.dmg as { contents: ReadonlyArray<{ name?: string }> }).contents[0]?.name;
+      assert.equal(dmgAppName(stable), "T3 Code (Beta).app");
+      assert.equal(dmgAppName(nightly), "T3 Code (Nightly).app");
+    }).pipe(
+      Effect.provide(
+        ConfigProvider.layer(
+          ConfigProvider.fromEnv({ env: { GITHUB_REPOSITORY: "pingdotgg/t3code" } }),
+        ),
+      ),
+    ),
+  );
+
   it.effect("omits update feeds for pull request preview builds", () =>
     Effect.gen(function* () {
       const preview = yield* createBuildConfig(

scripts/build-desktop-artifact.ts

@@ -63,6 +63,10 @@ import { ChildProcess, ChildProcessSpawner } from "effect/process";
 
 const LINUX_ICON_SIZES = [16, 22, 24, 32, 48, 64, 128, 256, 512] as const;
 const DESKTOP_APP_ID = "com.t3tools.t3code";
+
+// Squirrel.Mac renames an install named after its executable to the update's executable,
+// then relaunches from the old path. One executable name for every channel keeps it in place.
+const MAC_BUNDLE_FILENAME = "T3 Code (Beta)";
 const APPLE_TEAM_ID_PATTERN = /^[A-Z0-9]{10}$/u;
 
 const BuildPlatform = Schema.Literals(["mac", "linux", "win"]);
@@ -2829,6 +2833,7 @@ export const createBuildConfig = Effect.fn("createBuildConfig")(function* (
     const path = yield* Path.Path;
     const repoRoot = yield* RepoRoot;
     buildConfig.mac = {
+      executableName: MAC_BUNDLE_FILENAME,
       target: target === "dmg" ? [target, "zip"] : [target],
       icon: "icon.icns",
       category: "public.app-category.developer-tools",
@@ -2892,7 +2897,9 @@ export const createBuildConfig = Effect.fn("createBuildConfig")(function* (
         height: 432,
       },
       contents: [
-        { x: 166, y: 214, type: "file" },
+        // Name the app after its channel so a nightly installs beside stable. Squirrel.Mac
+        // never renames a bundle whose folder differs from its executable, so it stays put.
+        { x: 166, y: 214, type: "file", name: `${resolveDesktopProductName(version)}.app` },
         { x: 474, y: 214, type: "link", path: "/Applications" },
       ],
       iconSize: 120,