Step 5 of milestone 481. Replaces the linked-notes constellation, which had been
stale since note links were dropped (alembic 0024). The colour scheme stays.
packaging/icons.py draws the mark once and renders every variant from it: the
rounded tile (web, desktop), the maskable full-bleed web icon, and the Android
adaptive foreground. The detail (shaft, vane splits, glint) is cut out of the ink
with a mask rather than painted on in yellow, because the Android foreground is
now transparent and its alpha is also the themed-icon silhouette. The old
foreground was the opaque maskable tile, which a themed icon would have drawn as
a solid square.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
