refactor(config): remove unused barrel exports

Clean up unused re-exports from config barrel file

Remove 14 unused schema exports identified by knip analysis

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

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

src/config/index.ts

@@ -1,18 +1,5 @@
 export {
   OhMyOpenCodeConfigSchema,
-  AgentOverrideConfigSchema,
-  AgentOverridesSchema,
-  McpNameSchema,
-  AgentNameSchema,
-  HookNameSchema,
-  BuiltinCommandNameSchema,
-  SisyphusAgentConfigSchema,
-  ExperimentalConfigSchema,
-  RalphLoopConfigSchema,
-  TmuxConfigSchema,
-  TmuxLayoutSchema,
-  RuntimeFallbackConfigSchema,
-  FallbackModelsSchema,
 } from "./schema"
 
 export type {