Add Litematica exporter and integrate serde for serialization

- Introduced Litematica exporter with necessary data structures for Minecraft text generation.
- Added serde dependency for serialization support in multiple crates.
- Updated Cargo.toml files to include new dependencies and features.
- Created palette module for block palette management.

crates/lib/src/lib.rs

@@ -4,6 +4,7 @@ mod font;
 mod fonts;
 mod grid;
 mod models;
+mod palette;
 
 pub use engine::{GenerationOptions, TextBuilder};
 pub use error::{FontError, VoxelError};

crates/lib/src/palette.rs

@@ -0,0 +1,34 @@
+use crate::VoxelType;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct BlockPalette {
+    pub name: String,
+    pub author: Option<String>,
+    pub blocks: PaletteMappings,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PaletteMappings {
+    pub body: String,
+    pub outline: Option<String>,
+    pub shadow: Option<String>,
+}
+
+impl BlockPalette {
+    pub fn resolve(&self, voxel: &VoxelType) -> String {
+        match voxel {
+            VoxelType::Body => self.blocks.body.clone(),
+            VoxelType::Outline => self
+                .blocks
+                .outline
+                .clone()
+                .unwrap_or_else(|| "minecraft:air".to_string()),
+            VoxelType::Shadow => self
+                .blocks
+                .shadow
+                .clone()
+                .unwrap_or_else(|| "minecraft:air".to_string()),
+        }
+    }
+}