[Erry91]

Manifold::new / new_with_values return Result, but two kinds of malformed input still panic or are silently misread. This turns both into an Err, like the existing checks for boundary edges and buffer lengths.

1. Indices outside the vertex range

The remap table rmap was sized by pos.len() (three entries per vertex) rather than by the vertex count, so:

• an index >= pos.len() indexes past the end of rmap and panics (src/manifold/mod.rs:64);
• an index between the vertex count and pos.len() is silently read as vertex 0, because those rmap entries are never written.

// unit tetrahedron, 4 vertices, pos.len() == 12
let pos = [0., 0., 0., 1., 0., 0., 0., 1., 0., 0., 0., 1.];
let mut idx = [0, 2, 1, 0, 1, 3, 0, 3, 2, 1, 2, 3];
idx[0] = 99; Manifold::new(&pos, &idx); // panics: index out of bounds
idx[0] = 5;  Manifold::new(&pos, &idx); // Ok, vertex 5 taken as vertex 0

Now: Err("idx must refer to vertices in pos"), and rmap is sized by the vertex count.

2. NaN and infinite coordinates

A NaN coordinate was accepted by new and made the next compute_boolean panic. Non-finite coordinates (checked after the cast to Real, so this also catches f64 values that overflow f32 under the f32 feature) now give Err("pos must not contain NaN or infinite coordinates").

Tests

Four tests in a new test_input_validation module at the end of src/tests.rs, with the other tests (placed after the last module, so it does not conflict with #16, which adds to test_mesh_cleanup): a valid tetrahedron is accepted; index 99 and index 5 are errors; NaN, +∞ and −∞ are errors. The three error tests fail on main and pass with the change. cargo test passes for every feature set in CI ("", rayon, f32, f32,rayon), and cargo clippy reports the same warnings as on main.

Relation to #16

Complementary: #16 handles edges shared by more than two faces, this handles indices and coordinates. The two merge cleanly. With both, every malformed input in the probe I ran returns an Err: out-of-range index, NaN, ±∞, empty mesh, a single open triangle, a degenerate triangle, a flipped triangle, a duplicate face, the two tetrahedra from #14, and two cubes touching on an edge. No input panics.

Context: we feed boolmesh meshes imported from building models, which can be corrupt; an Err lets the caller report and skip the element instead of losing the process.

[komietty]

LGTM. Thank you for your PR.