Lantern architecture

Two entries:

• @jolly-pixel/lantern: Tour, TargetPath, TourRun, LanternSeen, Lantern. No Lit.
• @jolly-pixel/lantern/element: the Lit jolly-lantern overlay.

The element imports the root, never the reverse, so tour declarations and the step machine run under node --test.

• tour/: Tour parses TourStepOptions into frozen TourSteps with a zod/mini schema, whose issue path becomes TourDefinitionError.field; parseBody splits body text. In TourRun, one promise chain orders enter, cleanups and calls made while enter is pending. TargetSeek holds one step's search for its target: the one-second wait, the single warning, the late find.
• LanternSeen: the version per tour id, through a StorageAdapter.
• element/: TargetTracker calls run.seek each animation frame and measures what it finds, through a pane's chromeElement. spotlight/SpotlightPlacement turns that frame into the hole and the card position and paints the scrim, ring and card; the element repaints only when the new placement differs from the last one. StepInput holds the keys and the inputLayers layer of a passive step.
• The hole is a clip-path with the evenodd rule because clip-path also clips hit testing. Passive steps add a transparent shield over the hole.