perf(profiler): optimize hot paths from async-profiler

[szhatchenko]

Optimizations based on async-profiler analysis from https://uni.sirius-web.org:58443.

Profiles Analyzed

• Number of reports: 5 (most recent from last 24h)
• Time range: 2026-08-03 ~07:35-07:38 UTC
• Total samples across all profiles: 91,173
• Simulation: AgentModeling with Euler-Maruyama SDE solver (Neuronal_activity_modular_model_plain)

Top Hot Functions

1. SimpleEventDetector.detectEvent - 21,750 samples (24%) - per-step array cloning
2. EulerStochastic.doStep / integrationStep - 39,169 samples (43%) - simulation loop
3. SdeModel.dy_dt_deterministic / JavaBaseModel.dy_dt - 10,211 samples (11%) - derivative calculations
4. JavaBaseModel.firstPart / delay - 8,206 samples - linear search through sorted time list
5. updateStochasticValuesArrays - per-step HashMap copy

Changes

• SimpleEventDetector.detectEvent: Replace xNew.clone() with reusable scratch array (xEventScratch), eliminating per-step double[] allocation
• EulerStochastic.integrationStep: Pre-allocate scratch arrays for stochastic and deterministic derivatives, eliminating per-step double[] allocations
• SdeModel: Add allocation-free dy_dt_stochastic(time, x, output) and dy_dt_deterministic(time, x, output) overloads for solver usage
• EulerStochastic.updateStochasticValuesArrays: Swap HashMap references instead of copying, eliminating per-step HashMap allocation
• JavaBaseModel.firstPart(): Replace O(n) linear search with O(log n) binary search for delay lookups; add cache invalidation on history clear

Verification

• Maven build passes (mvn package -DskipTests)
• Ant build passes (cd src && ant compile)
• All tests pass (mvn -pl src test) - 697 tests, 1 pre-existing failure (WorkflowTest.testViewBuilderAnalysis, unrelated to these changes)

Co-Authored-By: Claude noreply@anthropic.com