fix: accept flags after positional args

[tasuku43]

Summary

• Accept flags even when they appear after positional args.
• Fixes unexpected usage: errors when running commands like:
  • gion manifest add --repo <repo> <WORKSPACE_ID> --no-prompt
  • gion manifest rm <WORKSPACE_ID> --no-prompt
  • gion apply --no-prompt

Details

• Adds shared argument normalization to move flags before positionals (respecting --).
• Applies it to manifest add, manifest rm, and manifest preset add/rm.
• Adds global arg normalization so global flags work after the command (e.g. apply --no-prompt).

Tests

• gofmt -w .
• go test ./...
• go vet ./...
• go build ./...