feat(postinstall): add branded GSD banner with version and next-step hint

scripts/postinstall.js

@@ -1,10 +1,45 @@
 #!/usr/bin/env node
 import { execSync } from 'child_process'
+import { createRequire } from 'module'
 import os from 'os'
+import { fileURLToPath } from 'url'
+import { dirname, resolve } from 'path'
 
+const __dirname = dirname(fileURLToPath(import.meta.url))
+const require = createRequire(import.meta.url)
+const pkg = require(resolve(__dirname, '..', 'package.json'))
+
+// Colors
+const cyan    = '\x1b[36m'
+const green   = '\x1b[32m'
+const yellow  = '\x1b[33m'
+const dim     = '\x1b[2m'
+const reset   = '\x1b[0m'
+
+const banner =
+  '\n' +
+  cyan +
+  '   ██████╗ ███████╗██████╗ \n' +
+  '  ██╔════╝ ██╔════╝██╔══██╗\n' +
+  '  ██║  ███╗███████╗██║  ██║\n' +
+  '  ██║   ██║╚════██║██║  ██║\n' +
+  '  ╚██████╔╝███████║██████╔╝\n' +
+  '   ╚═════╝ ╚══════╝╚═════╝ ' +
+  reset + '\n' +
+  '\n' +
+  `  Get Shit Done ${dim}v${pkg.version}${reset}\n` +
+  `  A standalone coding agent that plans, executes, and ships.\n` +
+  '\n' +
+  `  ${green}✓${reset} Installed successfully\n` +
+  `  ${dim}Run ${reset}${cyan}gsd${reset}${dim} to get started.${reset}\n`
+
+console.log(banner)
+
+// Install Playwright chromium for browser tools (non-fatal)
 const args = os.platform() === 'linux' ? '--with-deps' : ''
 try {
   execSync(`npx playwright install chromium ${args}`, { stdio: 'inherit' })
+  console.log(`\n  ${green}✓${reset} Browser tools ready\n`)
 } catch {
-  // Non-fatal — browser tools will show a clear error if playwright is missing
+  console.log(`\n  ${yellow}⚠${reset}  Browser tools unavailable — run ${cyan}npx playwright install chromium${reset} to enable\n`)
 }