Fix the Defined Benefits and Points System pensions so they can actually run

[marcelolafleur]

The non-US pension systems in pensions.py crash when used with a real Specifications object. We found this calibrating OG-BRA: Brazil's pension system (RGPS) is a defined benefits scheme, so OG-BRA is the first country model to use pension_system = "Defined Benefits" — and it crashes on the first solve. Same family of bugs as the Points System crash reported in #1075.

The cause is that these code paths were never updated after some parameters became time-varying: the functions pass arrays where the numba loops expect scalars, and scalars where they expect arrays. The existing tests didn't catch this because they feed the loops pre-cleaned inputs from mock objects instead of a real Specifications object.

Three changes (the third was added after testing a full transition path downstream):

• Fix the Defined Benefits and Points System paths so they run. They use the steady-state retirement age and earnings profile for now; full time variation stays open in Defined Benefits pension system not handling parameters object sizes correctly #1014. The NDC system needs more than this — its growth-rate settings aren't in default_parameters.json yet — so it remains unusable for now.
• Add tests that call the pension functions with a real Specifications object (these fail on master with the Bug: Points System crashes with ValueError due to p.retire being a list (plus subsequent TypingError) #1075 errors), plus a steady-state solve test with the DB system.
• Make the DB system solve the transition path, not just the steady state. Two pieces were missing: the benefit formulas reference pre-time-path wages and labor that nothing ever supplied (labor now comes from the model's initial condition — the same baseline object that initializes wealth — and wages are anchored to the period-0 wage of the current path), and there was no evaluation of DB amounts over the full (T, S, J) path for the TPI's aggregate revenue step (added as DB_3dim_loop, built from each cohort's own wage history so aggregates match household behavior; it reproduces the steady-state solution to machine precision on a constant path).

Fixes #1075. Part of #1014.

Tested: full pension and tax suites pass (71 tests); the DB steady state solves. Downstream check: the OG-BRA Defined Benefits calibration solves both the baseline and a reform transition path against this branch, passes the resource-constraint check on both, and hits its pension spending target to four decimals.

cc @rickecon @jdebacker

[codecov-commenter]

Codecov Report

❌ Patch coverage is 57.14286% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.29%. Comparing base (a12ecf5) to head (31f7cf2).

Files with missing lines	Patch %	Lines
ogcore/pensions.py	56.25%	21 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1167      +/-   ##
==========================================
- Coverage   73.37%   73.29%   -0.09%     
==========================================
  Files          21       21              
  Lines        5374     5410      +36     
==========================================
+ Hits         3943     3965      +22     
- Misses       1431     1445      +14     

Flag	Coverage Δ
unittests	73.29% <57.14%> (-0.09%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
ogcore/TPI.py	39.12% <100.00%> (+0.12%)	⬆️
ogcore/pensions.py	67.30% <56.25%> (-0.93%)	⬇️

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