fix(kimi): add ANTHROPIC_SMALL_FAST_MODEL support

- Add ANTHROPIC_SMALL_FAST_MODEL to all Kimi configuration templates
- Update installation scripts (npm, Unix, Windows) to include SMALL_FAST_MODEL
- Ensure Kimi API configuration matches official documentation format
- Bump version to 2.5.1 with updated changelog

Files updated:
- config/base-kimi.settings.json: Add SMALL_FAST_MODEL
- installers/install.sh: Update Unix template creation
- installers/install.ps1: Update PowerShell template creation
- scripts/postinstall.js: Update npm postinstall script
- All version files: Bump to 2.5.1

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@kaitranntt/ccs",
-  "version": "2.5.0",
+  "version": "2.5.1",
   "description": "Claude Code Switch - Instant profile switching between Claude Sonnet 4.5 and GLM 4.6",
   "keywords": [
     "cli",