refactor: update tool references from background_task to sisyphus_task

Update all references across:
- agent-usage-reminder: Update AGENT_TOOLS and REMINDER_MESSAGE
- claude-code-hooks: Update comment
- call-omo-agent: Update constants and tool restrictions
- init-deep template: Update example code
- tools/index.ts: Export sisyphus_task, remove background_task

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/claude-code-hooks/index.ts

@@ -239,7 +239,7 @@ export function createClaudeCodeHooksHook(ctx: PluginInput, config: PluginConfig
       const cachedInput = getToolInput(input.sessionID, input.tool, input.callID) || {}
 
       // Use metadata if available and non-empty, otherwise wrap output.output in a structured object
-      // This ensures plugin tools (call_omo_agent, task) that return strings
+      // This ensures plugin tools (call_omo_agent, sisyphus_task, task) that return strings
       // get their results properly recorded in transcripts instead of empty {}
       const metadata = output.metadata as Record<string, unknown> | undefined
       const hasMetadata = metadata && typeof metadata === "object" && Object.keys(metadata).length > 0

src/tools/call-omo-agent/constants.ts

@@ -4,4 +4,4 @@ export const CALL_OMO_AGENT_DESCRIPTION = `Spawn explore/librarian agent. run_in
 
 Available: {agents}
 
-Prompts MUST be in English. Use \`background_output\` for async results.`
+Pass \`resume=task_id\` to continue previous agent with full context. Prompts MUST be in English. Use \`background_output\` for async results.`

src/tools/call-omo-agent/tools.ts

@@ -142,6 +142,7 @@ async function executeSync(
         tools: {
           task: false,
           call_omo_agent: false,
+          sisyphus_task: false,
         },
         parts: [{ type: "text", text: args.prompt }],
       },

src/tools/index.ts

@@ -1,5 +1,3 @@
-import type { ToolDefinition } from "@opencode-ai/plugin"
-
 import {
   lsp_hover,
   lsp_goto_definition,
@@ -37,8 +35,26 @@ export { createSkillTool } from "./skill"
 export { getTmuxPath } from "./interactive-bash/utils"
 export { createSkillMcpTool } from "./skill-mcp"
 
+import {
+  createBackgroundOutput,
+  createBackgroundCancel,
+} from "./background-task"
+
+import type { PluginInput, ToolDefinition } from "@opencode-ai/plugin"
+import type { BackgroundManager } from "../features/background-agent"
+
+type OpencodeClient = PluginInput["client"]
+
 export { createCallOmoAgent } from "./call-omo-agent"
 export { createLookAt } from "./look-at"
+export { createSisyphusTask, type SisyphusTaskToolOptions, DEFAULT_CATEGORIES, CATEGORY_PROMPT_APPENDS } from "./sisyphus-task"
+
+export function createBackgroundTools(manager: BackgroundManager, client: OpencodeClient): Record<string, ToolDefinition> {
+  return {
+    background_output: createBackgroundOutput(manager, client),
+    background_cancel: createBackgroundCancel(manager, client),
+  }
+}
 
 export const builtinTools: Record<string, ToolDefinition> = {
   lsp_hover,