refactor(features): remove empty barrel files

Delete 2 empty barrel index.ts files:

- claude-tasks/index.ts

- mcp-oauth/index.ts

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/claude-tasks/index.ts

@@ -1,3 +0,0 @@
-export * from "./types"
-export * from "./storage"
-export * from "./session-storage"

src/features/mcp-oauth/index.ts

@@ -1,3 +0,0 @@
-export * from "./schema"
-export * from "./oauth-authorization-flow"
-export * from "./provider"