fix: accept solver stop times already reached

[Siel]

Summary

• accept diffsol's StopTimeAtCurrentTime result as authoritative in both closure and DSL/JIT ODE event loops
• preserve bolus reinitialization and continuation from infusion boundaries to later subject events
• remove the narrower duplicate stop-time tolerance that rejected valid TSIT45 stops
• add closure and JIT regressions using the 17-bolus/15-observation trajectory from the Pmetrics script8.R failure

Root cause

After bolus reinitialization, TSIT45 can land a few ULPs short of the requested event time. Diffsol applies its solver-specific tolerance and reports the stop as reached. The outer pharmsol event loop then requested the same stop again, received StopTimeAtCurrentTime, and rejected it with a narrower local 64-ULP check.

Diffsol already distinguishes a genuinely earlier invalid stop with StopTimeBeforeCurrentTime, so pharmsol should not second-guess StopTimeAtCurrentTime with a different tolerance.

Validation

• cargo test — pass
• cargo test --features dsl-jit — pass
• cargo test --all-features — pass
• new regression failed on v0.28.8 before the fix and passes in both closure and JIT paths after it
• existing infusion-boundary and dense-ULP regression tests pass
• debug/pharmsol_repro pharmsol-level examples pass:
  • script1, script2, script3
  • script6 with BDF, TSIT45, TRBDF2, and ESDIRK34
• direct *_diffsol controls continue to reproduce their expected raw Newton failures
• Pmetrics 3.2.5 rebuilt against this branch completes the original script8 simulation and a one-cycle fit

[codecov-commenter]

Codecov Report

❌ Patch coverage is 84.61538% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.89%. Comparing base (504b86a) to head (7bc7b6f).

Files with missing lines	Patch %	Lines
src/dsl/native.rs	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #344      +/-   ##
==========================================
+ Coverage   83.82%   83.89%   +0.07%     
==========================================
  Files          82       82              
  Lines       33983    33958      -25     
==========================================
+ Hits        28486    28489       +3     
+ Misses       5497     5469      -28     

Files with missing lines	Coverage Δ
src/simulator/equation/ode/mod.rs	88.88% <100.00%> (+1.02%)	⬆️
src/dsl/native.rs	67.73% <71.42%> (+0.40%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

Bencher Report

Project	pharmsol
Branch	fix/accept-current-stop-time
Testbed	mhovd-pgx

⚠️ WARNING: Truncated view!

The full continuous benchmarking report exceeds the maximum length allowed on this platform.

🐰 View full continuous benchmarking report in Bencher