wip: cache-tracking progress

rust/crates/api/src/lib.rs

@@ -1,5 +1,6 @@
 mod client;
 mod error;
+mod prompt_cache;
 mod sse;
 mod types;
 
@@ -8,6 +9,10 @@ pub use client::{
     AnthropicClient, AuthSource, MessageStream, OAuthTokenSet,
 };
 pub use error::ApiError;
+pub use prompt_cache::{
+    CacheBreakEvent, PromptCache, PromptCacheConfig, PromptCachePaths, PromptCacheRecord,
+    PromptCacheStats,
+};
 pub use sse::{parse_frame, SseParser};
 pub use types::{
     ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent, ContentBlockStopEvent,