Add card ui_schema validation guard and fix drift (#199)

[rosspeili]

Description

Fixes #199.

Adds a CI guard so every registry skill with an output card.json (ui_schema.type: card) has field keys that resolve in representative execute() JSON. Introduces skillware/core/ui_schema.py, fixtures for all 13 output-card skills, and aligns mica_module and pii_masker cards with actual return shapes. Documents the update-in-sync rule in CONTRIBUTING and TESTING. Also fixes the PDF form filler maintainer test to use tmp_path on Windows.

Type of Change

• Skill Upgrade — card.json fixes for mica_module and pii_masker
• Bug Fix — Windows-safe PDF form filler maintainer test
• Documentation — CONTRIBUTING, TESTING, contributor workflow
• Framework Feature — skillware/core/ui_schema.py, tests/test_card_ui_schema.py

Checklist (all PRs)

• Linked GitHub issue (Fixes #199)
• Scope matches the issue — no unrelated refactors
• black / flake8 pass locally
• pytest skills/ and pytest tests/ pass (309 tests)
• CHANGELOG.md updated under [Unreleased]
• examples/README.md — N/A (no example changes)
• pytest tests/test_registry_docs.py — N/A (no catalog/examples matrix changes)

New or updated skill

Card-only updates for compliance/mica_module and compliance/pii_masker — output fields now match execute() JSON. No manifest, logic, or catalog page changes.

Constitution and safety

N/A — validation and presentation metadata only; no runtime behavior changes except the unrelated test fix.

Related Issues

Fixes #199