fix(subagent): remove permission.question=deny override that caused zombie sessions

Child session creation was injecting permission: { question: 'deny' } which
conflicted with OpenCode's child session permission handling, causing subagent
sessions to hang with 0 messages after creation (zombie state).

Remove the permission override from all session creators (BackgroundManager,
sync-session-creator, call-omo-agent) and rely on prompt-level tool restrictions
(tools.question=false) to maintain the intended policy.

Closes #1711

src/features/background-agent/spawner.ts

@@ -58,17 +58,10 @@ export async function startTask(
   const parentDirectory = parentSession?.data?.directory ?? directory
   log(`[background-agent] Parent dir: ${parentSession?.data?.directory}, using: ${parentDirectory}`)
 
-  const inheritedPermission = (parentSession as any)?.data?.permission
-  const permissionRules = Array.isArray(inheritedPermission)
-    ? inheritedPermission.filter((r: any) => r?.permission !== "question")
-    : []
-  permissionRules.push({ permission: "question", action: "deny" as const, pattern: "*" })
-
   const createResult = await client.session.create({
     body: {
       parentID: input.parentSessionID,
       title: `Background: ${input.description}`,
-      permission: permissionRules,
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     } as any,
     query: {