Remove random initiative tie from runtime integrity test

[dajiaohuang]

Summary

test_combat_boundaries_and_private_knowledge_filter starts two same-modifier combatants without explicit initiative, then assumes combat_start always returns an active combat. Since #93 correctly requires an explicit ruling when initiative totals tie, the test intermittently receives a pending ruling and crashes while indexing a missing combat status.

This exact failure has occurred in unrelated PR #95 and #103 Python 3.12 full MCP jobs, while all feature-focused and Python 3.11 tests passed.

Acceptance criteria

• Make this test deterministic with distinct explicit initiative values (or explicitly resolve the tie contract if tie behavior is what it intends to test).
• Audit adjacent tests for the same “random initiative but unconditional active combat” assumption and fix only confirmed susceptible cases.
• Do not weaken the production explicit-tie ruling introduced by Require explicit initiative tie rulings #93.
• Verify the affected test repeatedly and run the relevant MCP suite/CI.

Reference

• packages/mcp/tests/test_runtime_integrity_mcp.py:2100-2140
• CI runs 33414864406 and 33415794987