Collect malformed-plugin samples to inform PluginValidationError diagnostics

Requested Update

Description

• Collect real-world malformed plugin YAML samples so we can later design
  better PluginValidationError diagnostics based on evidence rather than
  guesses.

Background and Motivation

• Pluginify PR #17 ports PluginValidationError from GeoIPS PR #1269. The wrapper
  works well for simple models, but for union models (e.g. sectors) one
  structural mistake can still produce 60+ error lines.
• We could add heuristics to pinpoint the actual root cause, but without
  real failure samples we would be designing for one anecdote. Better to
  collect samples first.

Alternative Solutions

• Skip the data-collection step and implement heuristics now based on the
  one observed case. Rejected because it risks misleading users on
  mistakes we have not yet seen.

Code to demonstrate issue

To submit a sample, comment on this issue with all four items below. See the follow-up comment for a worked example.

1. Bad YAML. Paste (or attach) the plugin YAML that failed validation.

2. Raw pydantic error. Run the snippet below, replacing the interface and model names with the ones that match your plugin (for example ConfigPluginModel from pluginify.pydantic_models.v1.configs), and the path with your bad YAML file. Paste the printed output.

   import yaml
   from pydantic import ValidationError
   from pluginify.pydantic_models.v1.<interface> import <YourPluginModel>
   
   with open("<path-to-your-bad-plugin>.yaml") as f:
       data = yaml.safe_load(f)
   
   try:
       <YourPluginModel>(**data)
   except ValidationError as exc:
       print(exc)
   

3. Current wrapped error. Try to load the plugin normally and copy the PluginValidationError message from the traceback:

   from pluginify.interfaces import <interface>
   
   <interface>.get_plugin("<your_plugin_name>")
   

4. One-line description. What were you trying to express in the plugin (for example, "static sector with a region block")?

Checklist for Completion

• Collect ~5-10 distinct real-world malformed plugin samples in this
  thread, each with the bad YAML, raw pydantic error, current wrapped
  error, and a short description (preferably one-line) of the user's intent (preferably one-line).
• Open a follow-up issue or PR to design diagnostic improvements once
  enough examples exist.