Add UK microsim guidance

[nikhilwoodruff]

No description provided.

[vahid-ahmadi]

Review Summary

Thanks for this comprehensive guide! I found a few critical issues that should be fixed before merging:

Critical Issues:

1. Line 3: Typo - double space in "PolicyEngine UK ONLY"
2. Line 454: Incorrect parameter - map_to="person" when age is already person-level
3. Line 774: Formatting - missing newline before section header

I'll add inline comments on these specific lines.

[vahid-ahmadi]

Line 3: Typo - there's a double space between "PolicyEngine" and "UK". Should be:

Guide for implementing policy reforms and microsimulation analysis in PolicyEngine UK ONLY projects.

[vahid-ahmadi]

Line 454: Incorrect parameter usage. The code has:

age = sim.calculate("age", map_to="person")

Since age is already a person-level variable, you don't need map_to="person". This line should either be:

age = sim.calculate("age")  # Already person-level

Or if you're trying to aggregate to household level, it should be:

age = sim.calculate("age", map_to="household")

[vahid-ahmadi]

Line 774: Formatting issue - missing newline before section header. There should be a blank line between the closing of the previous code block and the "### Conditional reform application" header.

Current:

    sim.tax_benefit_system.process_parameters()

Conditional reform application

Should be:

    sim.tax_benefit_system.process_parameters()

Conditional reform application

[vahid-ahmadi]

Additional Note: There are several incomplete code examples that should be filled in:

• Line 328: # Use the values... leaves the example incomplete
• Line 352: # Apply logic based on working_count... is truncated
• Line 796: # ... complex logic here should show actual implementation

These placeholder comments should either be completed with actual code or removed if they're meant to be filled in by the user.