fix: remove Node.js DEP0190 deprecation warning

Use platform-specific shell option (Windows only) instead of shell: true
to avoid deprecation warning in Node.js v22.9.0+.

Changes:
- bin/ccs.js: Change shell: true to shell: process.platform === 'win32'
- CHANGELOG.md: Document fix for v2.4.8
- VERSION: Bump to 2.4.8
- package.json: Bump to 2.4.8

Benefits:
- No deprecation warning on Windows
- Better performance on Unix (no shell overhead)
- Maintains Windows .cmd/.bat compatibility

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@kaitranntt/ccs",
-  "version": "2.4.7",
+  "version": "2.4.8",
   "description": "Claude Code Switch - Instant profile switching between Claude Sonnet 4.5 and GLM 4.6",
   "keywords": [
     "cli",