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- Removed outdated sections from `runtime-pipeline.md` and redirected to `render.md`.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/texm/src/error.rs

@@ -0,0 +1,61 @@
+use core::fmt;
+
+#[derive(Debug)]
+pub enum Error {
+    HeaderTooSmall {
+        size: usize,
+    },
+    InvalidMagic {
+        got: u32,
+    },
+    InvalidDimensions {
+        width: u32,
+        height: u32,
+    },
+    InvalidMipCount {
+        mip_count: u32,
+    },
+    UnknownFormat {
+        format: u32,
+    },
+    IntegerOverflow,
+    CoreDataOutOfBounds {
+        expected_end: usize,
+        actual_size: usize,
+    },
+    InvalidPageMagic,
+    InvalidPageSize {
+        expected: usize,
+        actual: usize,
+    },
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::HeaderTooSmall { size } => {
+                write!(f, "Texm payload too small for header: {size}")
+            }
+            Self::InvalidMagic { got } => write!(f, "invalid Texm magic: 0x{got:08X}"),
+            Self::InvalidDimensions { width, height } => {
+                write!(f, "invalid Texm dimensions: {width}x{height}")
+            }
+            Self::InvalidMipCount { mip_count } => write!(f, "invalid Texm mip_count={mip_count}"),
+            Self::UnknownFormat { format } => write!(f, "unknown Texm format={format}"),
+            Self::IntegerOverflow => write!(f, "integer overflow"),
+            Self::CoreDataOutOfBounds {
+                expected_end,
+                actual_size,
+            } => write!(
+                f,
+                "Texm core data out of bounds: expected_end={expected_end}, actual_size={actual_size}"
+            ),
+            Self::InvalidPageMagic => write!(f, "Texm tail exists but Page magic is missing"),
+            Self::InvalidPageSize { expected, actual } => {
+                write!(f, "invalid Page chunk size: expected={expected}, actual={actual}")
+            }
+        }
+    }
+}
+
+impl std::error::Error for Error {}