TEST-ONLY (R2-A Task 1 seam): fully reset the dual-chart container —
clears BOTH charts, drops planInitialized, and returns to "status"
mode — without requiring a live DOM/initToken the way destroyOdontogram()
does. Lets each test in a suite start from a clean slate instead of
leaking planInitialized/chart contents across tests in the same module
instance. Not part of the public API.
TEST-ONLY (R2-A Task 1 seam): fully reset the dual-chart container — clears BOTH charts, drops
planInitialized, and returns to "status" mode — without requiring a live DOM/initToken the way destroyOdontogram() does. Lets each test in a suite start from a clean slate instead of leakingplanInitialized/chart contents across tests in the same module instance. Not part of the public API.