Complete core systems test coverage improvements (epic 10.1.1)

[Copilot]

Implements all child tasks (10.1.2–10.1.8) of the test coverage epic, adding 166 tests and improving coverage from 90.25% to 90.95%.

Changes

SimEngine API coverage (10.1.3)

• 41 new tests for all public APIs: director_feed, explanations (query_timeline, explain_metric, explain_faction), progression helpers
• Error path coverage: uninitialized state, invalid views, tick limit enforcement
• Integration test validating progression updates on tick advance

FactionSystem RNG decoupling (10.1.4)

• Replaced brittle seed-based tests with DeterministicRNG injection
• State transitions now verified against config deltas (legitimacy, resources)

class DeterministicRNG:
    def __init__(self, uniform_value: float = 0.0):
        self._uniform_value = uniform_value

    def uniform(self, lo: float, hi: float) -> float:
        return max(lo, min(hi, self._uniform_value))

Persistence fidelity (10.1.5)

• 17 round-trip tests (save → load → save) for all subsystems
• Backwards compatibility tests for missing/unknown fields

Cross-system integration (10.1.6)

• 7 scenario tests: unrest cascades, faction rivalry, economy-environment feedback
• Marked @integration/@slow for selective CI execution

Performance guardrails (10.1.7)

• Tick limit enforcement for engine, CLI, service
• Timing thresholds (100 ticks < 10s)

AI/LLM mocking (10.1.8)

• ConfigurableMockProvider and AIPlayerMockProvider for OpenAI/Anthropic
• Gateway → LLM → Simulation flow coverage
• CI-friendly: no external API calls

Coverage Impact

Component	Before	After
SimEngine	85%	98%
AI/LLM	0-20%	74-97%
Total	90.25%	90.95%

Original prompt

"Issue 45 - 10.1.1 — Core systems test coverage improvements (epic)" to test agent

Created from Copilot CLI via the copilot delegate command.

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