fix: critical hooks bug - preserve all Claude Code settings

BREAKING BUG FIX: Hook installation was destroying existing Claude Code settings

- Fix critical data loss in --install-hook and --uninstall-hook commands
- Change ClaudeSettings to preserve ALL existing JSON settings via Data map
- Add automatic timestamped backup creation before any settings modification
- Implement surgical hook installation that adds to existing config structure
- Implement surgical hook removal that only removes shush hooks
- Prevent loss of user settings like includeCoAuthoredBy, themes, etc.
- Add comprehensive error handling for malformed settings files

This was a critical data loss bug that could destroy users' Claude Code configurations.
All existing settings are now preserved during hook operations.

Fixes: Users losing their Claude Code settings during hook installation
Added: Automatic backups with timestamp (settings.json.backup.TIMESTAMP)
Improved: Hook management now respects existing PostToolUse configurations

cmd/shush/main.go

@@ -12,7 +12,7 @@ import (
 	"github.com/carlosarraes/shush/internal/types"
 )
 
-var version = "0.2.2"
+var version = "0.2.3"
 
 func main() {
 	var cliArgs types.CLI