Pure planLaneMinting decides which tracks hold >1 mode's content and which managed
lane each item lands on; view.cpp applies it (I_FREEMODE/I_NUMFIXEDLANES/P_LANENAME/
I_FIXEDLANE) under one undo block, driven off the auto-tag detection tick. Manual lanes
and their items are never touched. Load-time reconcile rebuilds ownership from durable
lane names before reapplying active-mode visibility.
Drives fixed-lane C_LANEPLAYS for managed lanes only (name-keyed, ordinal-renumber
safe) in the view shell; diffs live track/item GUIDs on the panel timer to auto-tag
new content to the active mode, first-poll-guarded. Pure guid_diff + lane_keys
modules unit-tested; folds in Wave-1 polish.