Refactor documentation structure and add new specifications

- Updated MSH documentation to reflect changes in material, wear, and texture specifications.
- Introduced new `render.md` file detailing the render pipeline process.
- Removed outdated sections from `runtime-pipeline.md` and redirected to `render.md`.
- Added detailed specifications for `Texm` texture format and `WEAR` wear table.
- Updated navigation in `mkdocs.yml` to align with new documentation structure.

crates/msh-core/src/error.rs

@@ -0,0 +1,74 @@
+use core::fmt;
+
+#[derive(Debug)]
+pub enum Error {
+    Nres(nres::error::Error),
+    MissingResource {
+        kind: u32,
+        label: &'static str,
+    },
+    InvalidResourceSize {
+        label: &'static str,
+        size: usize,
+        stride: usize,
+    },
+    InvalidRes2Size {
+        size: usize,
+    },
+    UnsupportedNodeStride {
+        stride: usize,
+    },
+    IndexOutOfBounds {
+        label: &'static str,
+        index: usize,
+        limit: usize,
+    },
+    IntegerOverflow,
+}
+
+impl From<nres::error::Error> for Error {
+    fn from(value: nres::error::Error) -> Self {
+        Self::Nres(value)
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Nres(err) => write!(f, "{err}"),
+            Self::MissingResource { kind, label } => {
+                write!(f, "missing required resource type={kind} ({label})")
+            }
+            Self::InvalidResourceSize {
+                label,
+                size,
+                stride,
+            } => {
+                write!(
+                    f,
+                    "invalid {label} size={size}, expected multiple of stride={stride}"
+                )
+            }
+            Self::InvalidRes2Size { size } => {
+                write!(f, "invalid Res2 size={size}, expected >= 140")
+            }
+            Self::UnsupportedNodeStride { stride } => {
+                write!(
+                    f,
+                    "unsupported Res1 node stride={stride}, expected 38 or 24"
+                )
+            }
+            Self::IndexOutOfBounds {
+                label,
+                index,
+                limit,
+            } => write!(
+                f,
+                "{label} index out of bounds: index={index}, limit={limit}"
+            ),
+            Self::IntegerOverflow => write!(f, "integer overflow"),
+        }
+    }
+}
+
+impl std::error::Error for Error {}