Add portable device behavioral model skill

[swgiacomelli]

What changed

• add a portable device-behavioral-model Agent Skills package;
• define analysis, scoping, implementation, and review modes;
• route agents to the current normative standard and task-specific resource documents rather than copying policy into the skill; and
• link the skill from the organization standards README.

Why

The TCA9548A, VEML7700, and ADS1115 model exercises exposed a repeatable agent workflow: establish a minimum useful trace, preserve device/harness boundaries, challenge temporal and environmental seams, keep derivation independent, and require discriminating evidence. Encoding that procedure as a portable skill reduces repeated reasoning without making the skill a second normative surface.

The package uses the open Agent Skills directory format and avoids product-specific metadata, tool names, filesystem paths, language scaffolding, and copied standards text. Compatible agents can load or install the directory while the public organization documents remain the maintained source of truth.

Impact

This is a non-normative workflow aid. It does not change the device behavioral model standard, prescribe model packaging, introduce a support crate, or alter repository adoption requirements.

Validation

• skill-creator quick_validate.py: passed;
• python -m unittest discover -s tests -v: 19 passed;
• git diff --check: passed;
• verified every canonical guidance path referenced by the skill exists on main;
• audited the skill directory for product-specific metadata, tool names, absolute paths, and unfinished placeholders: none found.