fix(interpreter): seed $RANDOM PRNG per-instance#1222
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…quences Replace the per-access RandomState hash approach with a properly seeded LCG (linear congruential generator) stored per-interpreter instance. The PRNG is seeded from OS entropy at construction time and uses the glibc LCG constants (state * 1103515245 + 12345), matching real bash behavior. RANDOM=N reseeds the PRNG for deterministic replay. Uses AtomicU32 for interior mutability so $RANDOM can advance state in expand_variable(&self) while keeping the Interpreter Send+Sync. Closes #1180
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Summary
Closes #1180
RandomState::new()with a stored LCG PRNG state (AtomicU32) seeded from OS entropy at interpreter creationstate * 1103515245 + 12345) matching bash behaviorRANDOM=Nreseeding (assigning to RANDOM sets the PRNG seed, consistent with real bash)Test plan
test_random_different_instances— two Bash instances produce different first valuestest_random_reseed—RANDOM=42on two instances yields identical sequencestest_random_sequential_varies— three sequential calls produce varying values