fix: address Cubic round-3 P2/P3 issues

- Encode path segments with encodeURIComponent in HTTP API URLs
  to prevent broken requests when IDs contain special characters
- Remove unused readMessagesFromSDK from messages-reader.ts
  (production callers use local implementations; dead code)

src/hooks/session-recovery/storage.ts

@@ -1,7 +1,6 @@
 export { generatePartId } from "./storage/part-id"
 export { getMessageDir } from "./storage/message-dir"
 export { readMessages } from "./storage/messages-reader"
-export { readMessagesFromSDK } from "./storage/messages-reader"
 export { readParts } from "./storage/parts-reader"
 export { readPartsFromSDK } from "./storage/parts-reader"
 export { hasContent, messageHasContent } from "./storage/part-content"