perf(render): keep solid meshes resident

Keep all solid geometry GPU-resident during navigation. Use vertex-rate instancing, compact untextured vertices, vertex-cache ordering, and cached silhouette sources without culling geometry.

Cargo.toml

@@ -67,6 +67,7 @@ iced_widget = { git = "https://github.com/iced-rs/iced.git", rev = "23604ff22ab0
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 ocs_plugin_api = { path = "crates/ocs_plugin_api", features = ["host"] }
+meshopt = "0.6.2"
 i18n-embed = { version = "0.16", features = ["desktop-requester"] }
 rayon = "1"
 open = "5"