=== Task 3 deep dive: the silent period desync ===
entry_bar=3, exit_bar=5 fixed; Session period BAKED at 15m.

resample=15m, session=15m (COUPLED, correct): bars=1679   total_pips=-45.0
resample=30m, session=15m (DESYNCED, silent): bars=839    total_pips=0.0
resample=30m, session=30m (REBUILT blueprint): bars=839    total_pips=63.0

Observation: all three bootstrap+run with NO error. The desynced
middle run is silently wrong — the param system cannot couple the two
periods, and only a blueprint rebuild (not a sweep) gives a coherent 30m.
