Friendlier auto-upgrade messaging

Before:
  Upgrading Shopify CLI by running: `pnpm add -g @shopify/cli@latest`...

After:
  ✨ New version of Shopify CLI available! (3.94.3 → 3.95.0)
     Now upgrading by running: `pnpm add -g @shopify/cli@latest`...
  [package manager output]
  ╭─ success ──────────────────────────────╮
  │  Shopify CLI upgraded                  │
  │                                        │
  │  You're now on version 3.95.0.         │
  ╰────────────────────────────────────────╯

- Pre-message now states *what just happened* ("new version
  available") and shows the version range when known.
- Adds a `renderSuccess` banner after a successful upgrade so users
  get explicit confirmation instead of silence.
- The version range comes from `checkForCachedNewVersion`, which
  is already populated by `versionToAutoUpgrade()` upstream — no
  extra network call.

Author: alfonso-noriega

packages/cli-kit/src/public/node/upgrade.ts

@@ -12,6 +12,7 @@ import {
   getPackageManager,
 } from './node-package-manager.js'
 import {outputContent, outputDebug, outputInfo, outputToken, outputWarn} from './output.js'
+import {renderSuccess} from './ui.js'
 import {cwd, moduleDirectory, sniffForPath} from './path.js'
 import {exec, isCI} from './system.js'
 import {isPreReleaseVersion} from './version.js'
@@ -92,8 +93,23 @@ export async function runCLIUpgrade(options: RunCLIUpgradeOptions = {}): Promise
     if (!command) {
       throw new Error('Could not determine the command to run')
     }
-    outputInfo(outputContent`Upgrading Shopify CLI by running: ${outputToken.genericShellCommand(installCommand)}...`)
+    // Cache lookup — already populated by versionToAutoUpgrade() upstream, so this
+    // is just a synchronous cache read, no extra network call.
+    const newerVersion = checkForCachedNewVersion('@shopify/cli', CLI_KIT_VERSION)
+    const headline = newerVersion
+      ? `✨ New version of Shopify CLI available! (${CLI_KIT_VERSION} → ${newerVersion})`
+      : '✨ New version of Shopify CLI available!'
+    outputInfo(
+      outputContent`${headline}
+   Now upgrading by running: ${outputToken.genericShellCommand(installCommand)}...`,
+    )
     await exec(command, args, {stdio: 'inherit'})
+    renderSuccess({
+      headline: 'Shopify CLI upgraded',
+      body: newerVersion
+        ? `You're now on version ${newerVersion}.`
+        : "You're now on the latest version.",
+    })
   } else if (projectDir) {
     await upgradeLocalShopify(projectDir, CLI_KIT_VERSION)
   } else {