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- Remove outdated dependencies and update dependency versions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

commit/create_commit.rs

@@ -16,7 +16,9 @@ impl GitBare {
                 Some(object_selector::Selector::Revision(name)) => {
                     crate::sanitize::validate_revision(&name.revision)?;
                 }
-                Some(object_selector::Selector::Oid(_)) => {} // OID is always safe
+                Some(object_selector::Selector::Oid(oid)) => {
+                    crate::sanitize::validate_oid_hex(&oid.hex)?;
+                }
                 None => {} // will use branch name, already validated
             }
         }
@@ -30,7 +32,10 @@ impl GitBare {
             "creating commit"
         );
         let start_rev = match request.start_revision.clone().and_then(|s| s.selector) {
-            Some(object_selector::Selector::Oid(oid)) => oid.hex,
+            Some(object_selector::Selector::Oid(oid)) => {
+                crate::sanitize::validate_oid_hex(&oid.hex)?;
+                oid.hex
+            }
             Some(object_selector::Selector::Revision(name)) => name.revision,
             None => request.branch.clone(),
         };