docs: correct Goal 7 speed control notes

Agent-Logs-Url: https://github.com/bedaHovorka/interlockSim/sessions/377a2ef7-bc5a-45a9-a471-74d5fad657c6

Co-authored-by: bedaHovorka <5263405+bedaHovorka@users.noreply.github.com>

Author: Copilot

LONG_TERM_GOALS.md

@@ -222,7 +222,8 @@ Users can adjust simulation speed from slow motion (for detailed observation) to
 **Dependencies:** None (quick win)
 
 **Implementation Notes:**
-- kDisco already supports speed control; needs UI exposure
+- The simulation library interface used by the model (historically jDisco, now kDisco/KMP) runs in pure simulation time and has no native wall-clock speed control or synchronization.
+- Speed control is implemented externally via wall-clock throttling in `SimulationRunner` around `SimulationContext.run()`, preserving simulation semantics unchanged and requiring zero modifications to the `sim/` package.
 - Quick win - implement early for immediate value
 
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