Fix agent rule gaps causing repeated pconfigs mistakes

[majmin7]

Description

Clarify and extend the installed rules (claude_assets/rules/, cursor_assets/rules/) and the pconfigs-review skill checklist to cover pconfigs patterns that agents get wrong consistently.

Changes to pconfigs.md:

• Prefer pdefaults(MyConfig) over MyConfig() when wanting defaults
• Explicit rule against string registries / if/elif factories to pick submodule types
• __pconfigs__.py sentinels may contain TestSubdirs or TestManually markers (not just be empty)
• Every Pinned[T] field must have a pdefaults entry set to the Pinned sentinel
• Clarification of pinputs(self) vs self inside @pproperty
• @penv placement rule expanded with a code example
• Config inspection section substantially expanded: print-once-and-reuse pattern, cite the printed-config path, source vs printed config mental model

Changes to policies.md:

• Instance file rename rule reframed: child specialization restructuring (foo.py → foo/base.py) is the one permitted case; all other renames are not

Changes to pconfigs-review/SKILL.md:

• Section 3: Pin(...) only when the target field is typed Pinned[T]
• Section 5: @pconfiged class must implement runtime behavior, not just hold a config reference
• Section 5: all .construct() calls must happen in __init__, not inside methods
• Section 8 (new): check for redundant __pconfigs__.py files
• Reformatted multi-line checklist items to single-line

Related Issue

Closes #10

Motivation and Context

Each gap in the rules requires a manual correction loop when an agent violates it. Making the rules explicit and adding checklist items eliminates corrections before they happen.

How Has This Been Tested?

Rules and skill files are documentation — no automated tests apply. The checklist additions were validated against the specific failure modes they address, which were observed across multiple projects before this fix.

Screenshots (if appropriate):

N/A

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.