chore(nav): optimize internal connectivity between structured modules

[beginwebdev2002]

• Updated frontend/readme.md to cross link to .jules/rules/ui-ux-design.md and .jules/rules/design.md
• Refactored .jules/rules/ui-ux-design.md to follow strict 4-step bad practice -> problem -> best practice -> solution methodology.
• Refactored .jules/rules/design.md to follow strict 4-step methodology.
• Fixed frontmatter missing fields and removed extraneous ones.

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PR created automatically by Jules for task 2828094087346552131 started by @beginwebdev2002

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