Fix 21 logic errors in dice geometry, sizing, and category mapping

[maflot]

Bump to 1.3.0. Establish a single source of truth for category->pip-slot mapping: each data row is one pip placed at its category's factor-level index, with ndots shared between the plotted layout and the legend. This removes the paste0() id join and the reliance on scaled dots values.

Correctness fixes:

• character dots decoded to the wrong pip position (row-order dependent)
• n=6 plot layout did not match the legend design
• panel/legend slot-count desync (absent levels, drop=FALSE, faceting)
• non-injective dots palette crashed draw_panel
• paste0(cat,x,y) id collisions drew phantom pips / cross-contaminated aes
• pip diameters fed to GeomPoint size aesthetic (~24% too small, overflow); pips now drawn as true circleGrob mm circles
• mapped size renormalised per panel instead of globally
• min_fill inverted the size encoding for pip_scale < 0.25
• NA/invalid sizes mishandled (silent drop vs full-size resurrection)

Robustness / API:

• ndots required and validated (was an opaque base-R error)
• forward ... to layer(); restore unknown-parameter warnings
• validate pip_scale in (0,1]; clamp the pip-centre shift
• per-tile tile_df aesthetics (mapping alpha/linewidth no longer crashes)
• per-axis pip packing; proportional make_offsets padding
• graceful fallback for non-default coordinate systems
• clear error for >6 dot categories at build time

Docs / data:

• geom_dice() @examples uses long-format data (comma strings were never split)
• regenerate sample_dice_data1/2 to the documented 160-row structure

Add tests/testthat/test-logic-fixes.R covering every fixed issue. R CMD check --as-cran clean; full testthat suite passing.