Create cache module with core data structures

- [x] 1. Create cache module with core data structures
  - Create `src/cache.rs` module file
  - Define `CrcParamsCacheKey` struct with `width`, `poly`, and `reflected` fields
  - Implement `Debug`, `Clone`, `PartialEq`, `Eq`, and `Hash` traits for the cache key
  - Add module declaration to `src/lib.rs`

Author: onethumb

.kiro/specs/crc-params-caching/tasks.md

@@ -1,6 +1,6 @@
 # Implementation Plan
 
-- [ ] 1. Create cache module with core data structures
+- [x] 1. Create cache module with core data structures
   - Create `src/cache.rs` module file
   - Define `CrcParamsCacheKey` struct with `width`, `poly`, and `reflected` fields
   - Implement `Debug`, `Clone`, `PartialEq`, `Eq`, and `Hash` traits for the cache key

src/cache.rs

@@ -0,0 +1,20 @@
+/// Cache key for storing CRC parameters that affect key generation
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub(crate) struct CrcParamsCacheKey {
+    /// CRC width (32 or 64 bits)
+    pub width: u8,
+    /// Polynomial value used for CRC calculation
+    pub poly: u64,
+    /// Whether the CRC uses reflected input/output
+    pub reflected: bool,
+}
+
+impl CrcParamsCacheKey {
+    pub fn new(width: u8, poly: u64, reflected: bool) -> Self {
+        Self {
+            width,
+            poly,
+            reflected,
+        }
+    }
+}

src/lib.rs

@@ -124,6 +124,7 @@ use std::io::{Read, Write};
 
 mod algorithm;
 mod arch;
+mod cache;
 mod combine;
 mod consts;
 mod crc32;