refactor(athena): remove athena_council from plugin wiring

Drop the barrel export, tool-registry registration, and agent-tool-restriction entry for the deleted athena_council tool.

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

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

src/plugin/tool-registry.ts

@@ -13,7 +13,6 @@ import {
   builtinTools,
   createBackgroundTools,
   createCallOmoAgent,
-  createAthenaCouncilTool,
   createSwitchAgentTool,
   createLookAt,
   createSkillMcpTool,
@@ -173,11 +172,6 @@ export function createToolRegistry(args: {
     pluginConfig.agents,
     pluginConfig.categories,
   )
-  const athenaCouncilConfig = pluginConfig.agents?.athena?.council
-  const athenaCouncilTool = createAthenaCouncilTool({
-    backgroundManager: managers.backgroundManager,
-    councilConfig: athenaCouncilConfig,
-  })
 
   const isMultimodalLookerEnabled = !(pluginConfig.disabled_agents ?? []).some(
     (agent) => agent.toLowerCase() === "multimodal-looker",
@@ -274,7 +268,6 @@ export function createToolRegistry(args: {
     ...factories.createSessionManagerTools(ctx),
     ...backgroundTools,
     call_omo_agent: callOmoAgent,
-    athena_council: athenaCouncilTool,
     switch_agent: createSwitchAgentTool({
       client: ctx.client,
     }),