engine: read the files commands name through fieldcraft_io::fs

file.open, geometry.open, geometry.import.mesh and reopening a model's
geometry read through the io crate's file edge instead of SolidCraft's
vfs, so in the browser they see the files the page holds (the same
store saves write to). Natively it is the same capped regular-file read.
fieldcraft-geometry drops its path-based readers (read_file,
open_design_file, read_3mf_file): it works on bytes, and reading files
is the io crate's job.

Part of #119

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

crates/geometry/src/lib.rs

@@ -22,7 +22,7 @@ pub mod sample;
 #[cfg(feature = "scripts")]
 mod script;
 
-pub use design::{Design, FeatureError, MAX_DESIGN_BYTES, open_design, open_design_file};
+pub use design::{Design, FeatureError, MAX_DESIGN_BYTES, open_design};
 pub mod tagged_mesh;
 #[cfg(feature = "scripts")]
 pub use script::{MAX_SCRIPT_BYTES, script_design};
@@ -47,14 +47,6 @@ impl From<KernelError> for Error {
     }
 }
 
-/// Read a regular file of at most `max_bytes` through SolidCraft's file access (in the browser,
-/// the in-memory files the web host loaded). Opening a design or a 3MF package from these bytes
-/// ([`open_design`], [`tagged_mesh::read_3mf`]) lets the caller record a hash of exactly what it
-/// opened.
-pub fn read_file(path: &str, max_bytes: usize) -> Result<Vec<u8>> {
-    solidcraft_io::vfs::read(path, max_bytes).map_err(|e| Error::Invalid(format!("cannot read `{path}`: {e}")))
-}
-
 /// SolidCraft's linear modelling tolerance (mm): points closer than this are the same point.
 const LINEAR_TOLERANCE: f64 = solidcraft_geom::LINEAR_TOL;