feat(dev): add confirmation prompt to apply command (#96)

Add safety confirmation prompt to `core dev apply` before executing
shell commands. This prevents accidental execution of destructive
commands pasted from untrusted sources or generated by AI agents.

Changes:
- Add --yes/-y flag to skip confirmation prompt
- Show warning and require explicit "y" confirmation before execution
- Allow --dry-run to bypass confirmation (no actual execution)
- Use existing cli.Confirm with Required() for mandatory response

Usage:
  core dev apply --command="rm -rf ."     # Prompts for confirmation
  core dev apply --command="..." --yes    # Skips confirmation
  core dev apply --command="..." --dry-run # No execution, no prompt

Closes #81

Co-authored-by: Claude <noreply@anthropic.com>

pkg/dev/cmd_apply.go

@@ -32,6 +32,7 @@ var (
 	applyDryRun   bool
 	applyPush     bool
 	applyContinue bool // Continue on error
+	applyYes      bool // Skip confirmation prompt
 )
 
 // AddApplyCommand adds the 'apply' command to dev.
@@ -54,6 +55,7 @@ func AddApplyCommand(parent *cli.Command) {
 	applyCmd.Flags().BoolVar(&applyDryRun, "dry-run", false, i18n.T("cmd.dev.apply.flag.dry_run"))
 	applyCmd.Flags().BoolVar(&applyPush, "push", false, i18n.T("cmd.dev.apply.flag.push"))
 	applyCmd.Flags().BoolVar(&applyContinue, "continue", false, i18n.T("cmd.dev.apply.flag.continue"))
+	applyCmd.Flags().BoolVarP(&applyYes, "yes", "y", false, i18n.T("cmd.dev.apply.flag.yes"))
 
 	parent.AddCommand(applyCmd)
 }
@@ -101,6 +103,18 @@ func runApply() error {
 	}
 	cli.Blank()
 
+	// Require confirmation unless --yes or --dry-run
+	if !applyYes && !applyDryRun {
+		cli.Print("%s\n", warningStyle.Render(i18n.T("cmd.dev.apply.warning")))
+		cli.Blank()
+
+		if !cli.Confirm(i18n.T("cmd.dev.apply.confirm"), cli.Required()) {
+			cli.Print("%s\n", dimStyle.Render(i18n.T("cmd.dev.apply.cancelled")))
+			return nil
+		}
+		cli.Blank()
+	}
+
 	var succeeded, skipped, failed int
 
 	for _, repo := range targetRepos {