Face-tagged 3MF exchange: format spec, reader, geometry.import.mesh

docs/formats/tagged-mesh.md defines the exchange: 3MF Core with an optional
ft:face attribute per triangle (and ft:faces per object) in a ModelCraft
namespace. modelcraft_geometry::tagged_mesh::read_3mf reads it from bytes
(wasm), capping every size and count and range-checking every index and
coordinate. geometry.import.mesh adds the surfaces to the session, which keeps
them beside the open design and restores them when a command fails.

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

Cargo.toml

@@ -23,6 +23,10 @@ serde = { version = "1", features = ["derive"] }
 serde_json = { version = "1", features = ["float_roundtrip"] }
 log = "0.4"
 
+# 3MF packages (docs/formats/tagged-mesh.md): the same versions SolidCraft uses.
+zip = { version = "3", default-features = false, features = ["deflate"] }
+quick-xml = "0.41"
+
 # Geometry: SolidCraft's B-rep kernel (MIT OR Apache-2.0), pinned. Only crates/geometry uses it
 # (plan/adr/0001-libraries.md).
 solidcraft-geom = { git = "https://github.com/bherbruck/solidcraft", rev = "de1479029dd6821cffd28b70688a58e7f61f0cfd" }