Restrict tip deduction to qualifying occupations

[MaxGhenis]

Summary

• Restrict the federal tip income deduction to people who meet a new tipped-occupation requirement.
• Add a detailed_industry_recode person input so the gate can be refined independently of the current microdata wiring.
• Move the occupation-to-eligible-industry mapping into policyengine_us/parameters/gov/irs/deductions/tip_income/eligible_industries_by_occupation_recode.yaml.
• Exclude SSTB cases and add focused policy tests for eligible, ineligible, and industry-dependent cases.

Notes

• The legal rule requires the deduction to be limited to published tipped occupations and excludes SSTB contexts.
• policyengine-us currently only carries the coarse CPS POCCU2 occupation recode, so this PR uses a conservative approximation with an industry hook rather than pretending we already have the final detailed occupation and industry inputs.
• The industry mapping is now policy parameter data rather than hardcoded Python, so it can be adjusted without editing the formula.
• If occupation data is missing entirely, the new gate stays permissive so standalone calculations remain backward compatible.

Testing

• make format
• uv run python -m compileall policyengine_us/variables/gov/irs/income/taxable_income/deductions/tip_income policyengine_us/variables/household/demographic/person/detailed_industry_recode.py
• uv run policyengine-core test policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/tip_income/tip_income_deduction.yaml -c policyengine_us
• uv run policyengine-core test policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/tip_and_overtime_income_deduction.yaml -c policyengine_us
• uv run policyengine-core test policyengine_us/tests/policy/baseline/gov/states/in/tax/income/deductions/obbba_conformity/in_tip_income_deduction.yaml -c policyengine_us
• uv run policyengine-core test policyengine_us/tests/policy/baseline/gov/irs/income/taxable_income/deductions/senior_deduction/integration.yaml -c policyengine_us

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (edaf7b1) to head (66f09d5).
⚠️ Report is 17 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #7896      +/-   ##
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+ Coverage   97.26%   100.00%   +2.73%     
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  Files           5         3       -2     
  Lines          73        42      -31     
  Branches        2         0       -2     
===========================================
- Hits           71        42      -29     
+ Misses          1         0       -1     
+ Partials        1         0       -1     

Flag	Coverage Δ
unittests	100.00% <100.00%> (+2.73%)	⬆️

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