Add answer key for Supply Chain Analytics workshop

[beagandica]

Summary

Complete teacher reference for the cookie bakery linear optimization workshop, with verified solutions and Excel Solver setup guide.

Changes

New file: \content/english/supply-chain-analytics/answer-key.md\

Optimization formulation

• Decision variables, objective function, and 3 constraints (eggs, flour, sugar)
• Mathematical notation with kid-friendly explanations

Main problem solution

• Optimal: 5 chocolate chip + 3 sugar cookie batches = \ maximum profit
• Constraint verification table showing flour is the binding constraint
• Teacher tip on binding constraints and slack

Excel Solver setup

• Complete Solver dialog configuration table (objective, variables, constraints, integer, method)
• Excel formula reference for all cells
• Common pitfalls (Non-Negative checkbox, integer constraints)

Extra challenge (egg shortage)

• Optimal: 1 chocolate chip + 6 sugar cookie batches = \ profit
• Profit decreased by ; eggs become the binding constraint
• Discussion prompts about supply chain disruptions

Teacher resources

• Key concepts summary table (6 optimization concepts mapped to bakery examples)
• Common student Q&A (3 questions)

Languages affected

• English (primary)
• Brazilian Portuguese and Korean translations exist (math/Excel is language-agnostic). Answer keys for these languages added to backlog.

Notes

• All calculations verified against \Cookie_Bakery_Optimization_Answers.xlsx\
• File uses kebab-case (\�nswer-key.md) per answer key convention, while other workshop files use PascalCase
• Weight 15 chosen to sort after Challenge (weight 5) with room for future pages
• Pre-existing: duplicate space-named Excel files in directory (backlog item, not in this PR scope)

Testing

• Hugo build passes
• All language versions checked (EN primary; PT-BR, KO use same math)
• 10-model QA passed (3 clean convergence passes)
• All arithmetic verified against Excel answer file
• Follows answer key format (hidden: true, weight: 15)