feat: add corex-storage crate for unified storage abstraction

- Introduced corex-storage crate with support for local disk, S3-compatible, and Google Cloud Storage backends.
- Implemented StorageDriver trait for various storage backends.
- Added LocalFileStorage for local disk operations.
- Added S3Storage for S3-compatible object storage with multipart upload support.
- Added GcsStorage for Google Cloud Storage operations.
- Included error handling for storage operations.
- Added tests for each storage backend to ensure functionality.
- Created README.md for documentation and usage examples.
- Added Apache and MIT licenses for open-source compliance.

crates/mytheclipse-cache/src/traits.rs

@@ -0,0 +1,77 @@
+//! The core [`Cache`] and [`KeyEncoder`] traits.
+
+use std::borrow::Cow;
+use std::time::Duration;
+
+use async_trait::async_trait;
+
+/// Errors returned by cache operations.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum CacheError {
+    /// The backend could not be reached (e.g. Redis connection lost).
+    Io(String),
+    /// A value could not be serialized / deserialized.
+    Serialization(String),
+    /// A key could not be encoded for the backend.
+    Key(String),
+}
+
+impl std::fmt::Display for CacheError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Io(s) => write!(f, "cache io: {s}"),
+            Self::Serialization(s) => write!(f, "cache serialization: {s}"),
+            Self::Key(s) => write!(f, "cache key: {s}"),
+        }
+    }
+}
+
+impl std::error::Error for CacheError {}
+
+/// A generic byte-oriented cache.
+///
+/// Real caches operate on bytes or strings; typed convenience is layered on
+/// top (see [`crate::memory::typed::TypedCache`], behind `cache-aside`).
+/// Implementors control the value format.
+#[async_trait]
+pub trait Cache: Send + Sync {
+    /// Fetches a value by key. `None` indicates a miss.
+    async fn get(&self, key: &str) -> Result<Option<Vec<u8>>, CacheError>;
+    /// Stores a value under `key`, optionally expiring after `ttl`.
+    async fn set(&self, key: &str, value: Vec<u8>, ttl: Option<Duration>)
+        -> Result<(), CacheError>;
+    /// Removes a key.
+    async fn invalidate(&self, key: &str) -> Result<(), CacheError>;
+    /// Removes all entries.
+    async fn clear(&self) -> Result<(), CacheError>;
+}
+
+/// Keys given to the byte-oriented [`Cache`] are `&str`, but concrete backends
+/// may need richer keys. [`KeyEncoder`] turns typed keys into canonical strings.
+pub trait KeyEncoder {
+    /// The "shape" of a key, e.g. `"user:{id}:profile"`.
+    fn encode<C: Into<Cow<'static, str>>, R: std::fmt::Display>(parts: (C, R)) -> String;
+}
+
+/// A blanket implementation that formats `{collection}:{id}`.
+pub struct DefaultKeyEncoder;
+
+impl KeyEncoder for DefaultKeyEncoder {
+    fn encode<C: Into<Cow<'static, str>>, R: std::fmt::Display>(parts: (C, R)) -> String {
+        format!("{}:{}", parts.0.into(), parts.1)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn default_key_encoder_formats() {
+        assert_eq!(DefaultKeyEncoder::encode(("user", 42)), "user:42");
+        assert_eq!(
+            DefaultKeyEncoder::encode(("session", "abc-123")),
+            "session:abc-123"
+        );
+    }
+}