feat(mosaic): migrate install wizard from v0 to v1 (#103)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/mosaic/src/platform/detect.ts

@@ -0,0 +1,39 @@
+import { existsSync } from 'node:fs';
+import { join } from 'node:path';
+import { homedir, platform } from 'node:os';
+
+export type ShellType = 'zsh' | 'bash' | 'fish' | 'powershell' | 'unknown';
+
+export function detectShell(): ShellType {
+  const shell = process.env['SHELL'] ?? '';
+  if (shell.includes('zsh')) return 'zsh';
+  if (shell.includes('bash')) return 'bash';
+  if (shell.includes('fish')) return 'fish';
+  if (platform() === 'win32') return 'powershell';
+  return 'unknown';
+}
+
+export function getShellProfilePath(): string | null {
+  const home = homedir();
+
+  if (platform() === 'win32') {
+    return join(home, 'Documents', 'PowerShell', 'Microsoft.PowerShell_profile.ps1');
+  }
+
+  const shell = detectShell();
+  switch (shell) {
+    case 'zsh': {
+      const zdotdir = process.env['ZDOTDIR'] ?? home;
+      return join(zdotdir, '.zshrc');
+    }
+    case 'bash': {
+      const bashrc = join(home, '.bashrc');
+      if (existsSync(bashrc)) return bashrc;
+      return join(home, '.profile');
+    }
+    case 'fish':
+      return join(home, '.config', 'fish', 'config.fish');
+    default:
+      return join(home, '.profile');
+  }
+}