Fix random number generator warnings

[Mani212005]

Description This PR addresses the random number generator warnings that were causing ~45+ UserWarnings across the test suite. The warnings indicated that models could be non-reproducible when RNG is not explicitly specified.

Changes Made:

1. Added shared rng fixture (tests/conftest.py)
   • Created a pytest fixture that provides a deterministic [random.Random(42)]( instance
   • Can be used across all test files for reproducible randomness
2. Fixed Conway's Game of Life example ([model.py]
   • Added [random=self.random]) parameter to initialization
   • Ensures the grid uses the model's seeded RNG for reproducibility
3. Added tests using the rng fixture (tests/test_discrete_space.py)
   • test_orthogonal_moore_grid_with_rng: Tests Moore grid with provided RNG
   • test_orthogonal_von_neumann_grid_with_rng: Tests Von Neumann grid with provided RNG
   • test_cell_agent_with_rng: Tests CellAgent with provided RNG

Testing:

pytest tests/test_discrete_space.py -v

Result: 30 passed

pytest tests/ -v 2>&1 | grep -i "random number generator not specified"

Result: No warnings found

Impact ✅ Eliminates all "Random number generator not specified" warnings ✅ Improves model reproducibility ✅ No breaking changes - backwards compatible ✅ Provides pattern for future test development with the rng fixture

Closes # 2904 part 2.1 . Thank you.

[github-actions[bot]]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 +0.1% [-0.2%, +0.5%]	🔵 +1.0% [+0.9%, +1.1%]
BoltzmannWealth	large	🔵 +3.0% [-13.4%, +23.9%]	🔵 +2.3% [-0.6%, +5.1%]
Schelling	small	🔵 +0.1% [-0.1%, +0.3%]	🔵 -0.8% [-0.9%, -0.6%]
Schelling	large	🔵 +6.5% [-10.5%, +25.1%]	🔵 +10.8% [-9.9%, +41.0%]
WolfSheep	small	🔵 -0.7% [-0.9%, -0.5%]	🔵 -0.2% [-0.3%, -0.1%]
WolfSheep	large	🔵 +12.6% [-27.8%, +66.9%]	🔵 +21.2% [-14.0%, +62.9%]
BoidFlockers	small	🔵 +1.2% [+0.8%, +1.6%]	🔵 +0.9% [+0.8%, +1.0%]
BoidFlockers	large	🔵 +1.4% [+1.0%, +1.8%]	🔵 +0.5% [+0.3%, +0.7%]