feat(agents): add OmO orchestrator agent

- Add OmO agent: powerful AI orchestrator for complex task delegation
- Implements parallel background agent execution and todo-driven workflows
- Emphasizes aggressive subagent delegation with 7-section prompt structure

Co-authored-by: huynguyen03dev <[email protected]>
🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

Author: code-yeongyu

src/agents/index.ts

@@ -1,4 +1,5 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
+import { omoAgent } from "./omo"
 import { oracleAgent } from "./oracle"
 import { librarianAgent } from "./librarian"
 import { exploreAgent } from "./explore"
@@ -7,6 +8,7 @@ import { documentWriterAgent } from "./document-writer"
 import { multimodalLookerAgent } from "./multimodal-looker"
 
 export const builtinAgents: Record<string, AgentConfig> = {
+  OmO: omoAgent,
   oracle: oracleAgent,
   librarian: librarianAgent,
   explore: exploreAgent,
@@ -17,4 +19,3 @@ export const builtinAgents: Record<string, AgentConfig> = {
 
 export * from "./types"
 export { createBuiltinAgents } from "./utils"
-export { BUILD_AGENT_PROMPT_EXTENSION } from "./build"