feat(athena): split into athena (interactive) and athena-junior (subagent)

Split the Athena council orchestrator into two distinct agents:
- athena: primary mode, interactive prompt with Question tool and switch_agent
- athena-junior: subagent mode, non-interactive prompt with structured JSON output

Key changes:
- Create athena-junior-agent.ts factory (mode=subagent, denies question+call_omo_agent)
- Revert athena agent.ts to primary mode (no env var switching)
- Make buildAthenaRuntimeGuidance mode-aware (strips action_paths for non-interactive)
- Add mode parameter to council_finalize tool
- Register athena-junior in builtin-agents, tool-config, model-requirements
- Replace "athena" with "athena-junior" in call_omo_agent ALLOWED_AGENTS
- Update all tests for new architecture

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

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

src/plugin-handlers/tool-config-handler.ts

@@ -136,6 +136,16 @@ export function applyToolConfig(params: {
       question: questionPermission,
     };
   }
+  const athenaJunior = agentByKey(params.agentResult, "athena-junior");
+  if (athenaJunior) {
+    athenaJunior.permission = {
+      ...athenaJunior.permission,
+      task: "allow",
+      prepare_council_prompt: "allow",
+      council_finalize: "allow",
+      question: "deny",
+    };
+  }
 
   params.config.permission = {
     webfetch: "allow",