feat: add Fix command workspace grammar — 0.9.0

[silversurfer562]

Summary

• add Fix-first intake, preview, execution, and receipt workspace views
• add packaged semantic design tokens plus widget and Markdown workspace renderers
• enforce explicit-action, script-safety, dark-mode, accessibility, and portable postback contracts
• prepare synchronized 0.9.0 package/plugin release metadata

Verification

• 843 tests passed
• pre-commit all-files passed
• wheel and sdist built; twine check passed
• emitted action JavaScript parsed with Node
• dark primary contrast computed at WCAG AA
• FORM_THEME_CSS 12,174 / 12,288 bytes
• CSS_WORKSPACE 5,634 / 6,144 bytes

Review

• Antigravity cross-review: 12 sent / 0 omitted; 4 real findings fixed
• Claude cross-review: 12 sent / 0 omitted; 10 real findings fixed, 4 rejected
• three-seat roundtable: unanimous hold before corrections; all five chair-approved correction clusters implemented