Add left and right notches to brick outline

[parthdagia05]

Adds interlocking notches to the brick outline (path2):

• Right edge - one concave semicircular groove per argument slot, each centred a fixed offset below its slot, so grooves stay aligned with the arguments regardless of their heights.
• Left edge - a single convex tab where the brick plugs into its parent, aligned with the top right groove. Its radius is one stroke width smaller than the groove so the two seat together cleanly.

The left tab is excluded from the brick's width/height (otherwise connected bricks would be pushed apart) and reported separately as leftNotchDepth, which the Path view uses as a gutter so the tab isn't clipped. The label is centred on the notch line.

Both notches are off by default. Added a Storybook playground (argCount /argHeight / left+right toggles) to check alignment, and tests covering groove count, tab alignment, dimensions, label position, and path closure.