Replace the O(objects) linear scan inside wires_for_block() with a
sort_cache keyed by geometry_epoch. On a cache miss the index is built
once by scanning all document objects; subsequent calls within the same
epoch do an O(1) HashMap lookup (block_handle → entity→sort map).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Add two complementary render caches that make mouse navigation essentially
free regardless of file size:
Option A – Wire tessellation cache: entity_wires_arc() caches the
tessellated Vec<WireModel> keyed by geometry_epoch and returns an Arc,
so navigation frames (no preview wires) incur zero Vec clones and zero
tessellation work. Primitive::wires changed to Arc<Vec<WireModel>>.
Option B – GPU buffer cache: Pipeline stores cached_epoch; prepare()
skips all upload_wires/hatches/images/meshes calls when the epoch is
unchanged, writing only the 192-byte camera uniform instead.
geometry_epoch is a process-wide AtomicU64 incremented by every Scene
mutation (add/erase entity, selection, layer visibility, layout switch,
populate_*, grip, transform, copy, clear, preview wires). Using a global
counter rather than a per-scene counter prevents two tabs that happen to
have the same local bump count from sharing a cached_epoch value, which
was causing the first file's geometry to remain on screen after opening a
second file.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
