docs: Update core documentation with Structural Testing Contract

docs/guide_simulations.md

@@ -1,4 +1,14 @@
-# Verification & Simulation Framework
+## Structural Testing Contract
+
+To maintain the integrity of the test suite and ensure that AI-driven test modifications do not create false positives ("mock-rot"), the following rules apply to all testing within this project:
+
+1. **Ban on Arbitrary Core Mocking:** Tier 3 workers are strictly forbidden from using `unittest.mock.patch` to bypass or stub core infrastructure (e.g., event queues, `ai_client` internals, threading primitives) unless explicitly authorized by the Tier 2 Tech Lead for a specific boundary test. 
+2. **`live_gui` Standard:** All integration and end-to-end testing must utilize the `live_gui` fixture to interact with a real instance of the application via the Hook API. Bypassing the hook server to directly mutate GUI state in tests is prohibited.
+3. **Artifact Isolation:** All test-generated artifacts (logs, temporary workspaces, mock outputs) MUST be written to the `tests/artifacts/` or `tests/logs/` directories. These directories are git-ignored to prevent repository pollution.
+
+---
+
+## Verification & Simulation Framework
 
 [Top](../Readme.md) | [Architecture](guide_architecture.md) | [Tools & IPC](guide_tools.md) | [MMA Orchestration](guide_mma.md)