fix(background-agent): inherit parent session directory for background tasks

Background tasks were defaulting to $HOME instead of the parent session's
working directory. This caused background agents to scan the entire home
directory instead of the project directory, leading to:
- High CPU/memory load from scanning unrelated files
- Permission errors on system directories
- Task failures and timeouts

The fix retrieves the parent session's directory before creating a new
background session and passes it via the query.directory parameter.

Files modified:
- manager.ts: Look up parent session directory in launch()
- call-omo-agent/tools.ts: Same fix for sync mode
- look-at/tools.ts: Same fix for look_at tool
- sisyphus-task/tools.ts: Same fix + interface update for directory prop
- index.ts: Pass directory to sisyphusTask factory

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

@@ -145,11 +145,23 @@ async function executeSync(
     sessionID = args.session_id
   } else {
     log(`[call_omo_agent] Creating new session with parent: ${toolContext.sessionID}`)
+    const parentSession = await ctx.client.session.get({
+      path: { id: toolContext.sessionID },
+    }).catch((err) => {
+      log(`[call_omo_agent] Failed to get parent session:`, err)
+      return null
+    })
+    log(`[call_omo_agent] Parent session dir: ${parentSession?.data?.directory}, fallback: ${ctx.directory}`)
+    const parentDirectory = parentSession?.data?.directory ?? ctx.directory
+
     const createResult = await ctx.client.session.create({
       body: {
         parentID: toolContext.sessionID,
         title: `${args.description} (@${args.subagent_type} subagent)`,
       },
+      query: {
+        directory: parentDirectory,
+      },
     })
 
     if (createResult.error) {