Add the modelcraft-decks crate (empty: error type only) (#19)

So the Abaqus, Nastran and LS-DYNA writer tasks add their modules in parallel.


Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

Co-authored-by: jyviko <[email protected]>
Co-authored-by: Claude Opus 5.5 <[email protected]>

crates/decks/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "modelcraft-decks"
+description = "ModelCraft's solver decks: Abaqus input, Nastran bulk data and LS-DYNA keyword writers (and later readers)"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+modelcraft-model = { workspace = true }
+thiserror = { workspace = true }

crates/decks/src/lib.rs

@@ -0,0 +1,20 @@
+//! Solver decks: the solver-neutral model written as Abaqus input, Nastran bulk data and LS-DYNA
+//! keyword files. Each format is its own module (`abaqus`, `nastran`, `lsdyna`), written from the
+//! vendor's public reference manual in our own words; examples and expected files are our own.
+//! Writers read [`modelcraft_model::Model`] and its `resolve()` result, never another format.
+#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
+#![forbid(unsafe_code)]
+
+#[derive(Debug, Clone, PartialEq, thiserror::Error)]
+pub enum Error {
+    /// The model has something this format cannot express (named, with the format).
+    #[error("not supported by {format}: {what}")]
+    Unsupported { format: &'static str, what: String },
+    /// The model is not ready to write (its check failed).
+    #[error(transparent)]
+    Model(#[from] modelcraft_model::Error),
+    #[error("limit reached: {0}")]
+    Limit(String),
+}
+
+pub type Result<T> = std::result::Result<T, Error>;