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/agents/athena/council-runtime-guidance.ts

@@ -50,12 +50,25 @@ export function resolveCouncilIntent(intent?: string): CouncilIntent | null {
     : null
 }
 
-export function buildAthenaRuntimeGuidance(intent: CouncilIntent): string {
+export type CouncilGuidanceMode = "interactive" | "non-interactive"
+
+export function buildAthenaRuntimeGuidance(intent: CouncilIntent, mode: CouncilGuidanceMode = "interactive"): string {
+  let guidanceContent = RUNTIME_GUIDANCE_BY_INTENT[intent].trim()
+
+  if (mode === "non-interactive") {
+    guidanceContent = stripActionPaths(guidanceContent)
+  }
+
   return [
     "<athena_runtime_guidance>",
     "source: council_finalize",
     `intent: ${intent}`,
-    RUNTIME_GUIDANCE_BY_INTENT[intent].trim(),
+    `mode: ${mode}`,
+    guidanceContent,
     "</athena_runtime_guidance>",
   ].join("\n\n")
 }
+
+function stripActionPaths(guidance: string): string {
+  return guidance.replace(/<runtime_action_paths>[\s\S]*?<\/runtime_action_paths>/g, "").trim()
+}