Adds a third layout option alongside Stacked and Split. In Draw mode a
canvas overlay covers the scripture panel; the Pointer Events API routes
Apple Pencil input to perfect-freehand strokes while letting finger
touches fall through for normal scrolling. A floating toolbar provides
pen, highlighter, and eraser tools, six color swatches, S/M/L sizes,
undo, clear, and a Done button to return to Stacked view.
Strokes are stored as inkStrokes[] on each chunk and rendered as a
read-only transparent canvas overlay (InkLayer) in Stacked/Split modes.
migrateChunk is updated so all existing chunks get inkStrokes: [] on
first load.
Also adds a simple in-memory rate limiter on auth endpoints (10 attempts
per 15 min per IP).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>