YAML frontend: support direct use of key:value dict for args, params, etc instead of lists of name:+value: dicts

Description

The YAML launch syntax is overly verbose for providing:

• include: arguments
• node: parameters
• set_remap: entries
• set_parameter: entries

All look like:

include:
  arg:
    - name: argname
      value: argvalue

I propose we allow an additional usage pattern that directly uses mappings (dicts)

include:
  arg:
    argname: argval
    argname2: argval2

For all these mapping types. This would not break existing usage since the check would be

1. sequence? check for name: and value:
2. mapping? iterate over key+value pairs

Motivation

Increase intuitive/idiomatic use of YAML as a frontend, decrease verboseness

Design / Implementation Considerations

No response

Additional Information

No response

Start by locating the YAML frontend entry points for include, node, set_remap, and set_parameter, then inspect any parsing tests for their current list-based syntax. Done means direct key-value mappings work for all four cases while the existing name/value list form remains supported.