refactor(cache): redesign cache system with structured keys and improved performance

- Add repo_path parameter to cached_response and cached_vec_response functions
- Implement structured cache key format with namespace, repo_path, and request proto
- Replace global cache with Moka in-memory cache using weight-based eviction
- Set 256MB memory cap with 10-minute TTL and 2-minute TTI policy
- Add metrics collection for cache operations and evictions
- Implement efficient repo-scoped invalidation using key structure
- Add detailed documentation comments explaining cache architecture
- Remove outdated dependencies and update dependency versions
- Add error handling for encoding failures in cache operations
- Optimize Vec responses with length-delimited encoding and pre-allocation

macros.rs

@@ -4,7 +4,7 @@
 //! and validating revision strings before use.
 
 /// Extract a revision string from an optional ObjectSelector, applying
-/// validation to revision names. OID hex strings are always safe.
+/// validation to revision names and OID hex strings.
 ///
 /// Returns "HEAD" when selector is None.
 ///
@@ -15,7 +15,10 @@
 macro_rules! resolve_revision {
     ($selector:expr) => {{
         match $selector.and_then(|s| s.selector) {
-            Some($crate::pb::object_selector::Selector::Oid(oid)) => oid.hex,
+            Some($crate::pb::object_selector::Selector::Oid(oid)) => {
+                $crate::sanitize::validate_oid_hex(&oid.hex)?;
+                oid.hex
+            }
             Some($crate::pb::object_selector::Selector::Revision(name)) => {
                 $crate::sanitize::validate_revision(&name.revision)?;
                 name.revision
@@ -25,7 +28,10 @@ macro_rules! resolve_revision {
     }};
     ($selector:expr, $default:expr) => {{
         match $selector.and_then(|s| s.selector) {
-            Some($crate::pb::object_selector::Selector::Oid(oid)) => oid.hex,
+            Some($crate::pb::object_selector::Selector::Oid(oid)) => {
+                $crate::sanitize::validate_oid_hex(&oid.hex)?;
+                oid.hex
+            }
             Some($crate::pb::object_selector::Selector::Revision(name)) => {
                 $crate::sanitize::validate_revision(&name.revision)?;
                 name.revision