Add named templates with interactive prompts for `jp query`

Add support for named templates that can be defined in configuration files and used with interactive prompts for missing template variables.

Context

Currently, jp query supports basic templating with the --template flag, where template variables are resolved from the template.values configuration. However, users must manually configure all template values in advance, and there's no way to define reusable named templates.

This enhancement would allow users to define named templates in their configuration files and use them with a simple command like jp query --template <template_name>. When template variables are not pre-configured, the system would interactively prompt the user to provide values using the existing inquire crate integration.

Alternatives

Users can currently work around this by:

• Pre-defining all template values in template.values config
• Using the existing --template flag with manually crafted queries
• Creating shell scripts or aliases to wrap common query patterns

However, these alternatives require more setup and don't provide the interactive experience that would make templates truly user-friendly.

Proposed Implementation

Extend the existing template system to support named templates stored in configuration files. Add a new CLI flag --template-field=key=value to allow setting template variables directly from the command line. When template variables are undefined, use the inquire crate to prompt users interactively.

The implementation would involve:

1. Adding a templates section to the configuration schema
2. Modifying the query command to accept template names
3. Integrating interactive prompts for undefined variables
4. Supporting both CLI-provided and config-provided template values

Tasks

Extend the Template configuration struct to support named templates

• Add --template-field CLI argument parsing to the query command
• Integrate inquire prompts for missing template variables
• Update template rendering logic to handle named templates
• Add configuration file examples and documentation

Resources

blob/main/crates/jp_config/src/template.rs
blob/main/crates/jp_cli/src/cmd/query.rs#L28-L66
blob/main/crates/jp_cli/src/cmd/query.rs#L295-L305

Start by reading crates/jp_config/src/template.rs and the query command sections at crates/jp_cli/src/cmd/query.rs#L28-L66 and #L295-L305. Trace the existing template configuration, --template handling, and inquire integration before deciding how named templates and --template-field should fit together. Done means configuration examples, named-template rendering, CLI-provided values, and prompts for missing variables are covered.