fix: include full recipe parameter details in load/discovery output

[DOsinga]

When loading or discovering subrecipes, the load tool and source discovery only exposed parameter names (e.g., (params: foo, bar)). This left the agent without the type, requirement, description, default, or select options it needs to correctly populate the parameters field when delegating.

This change adds a format_parameters helper that renders full parameter metadata:

Parameters:
  - repo_url (string, required): The repository URL to analyze
  - depth (number, optional, default: "3"): How deep to scan
  - format (select, required, options: [json, markdown]): Output format

This is included in both:

• Source discovery — the description shown when listing available sources
• Load content — the content injected into context when a source is loaded

Fixes #7288