test(agent-loop): use current persona slots in admission harness

Adopt master’s explicit personaPrefix/personaSuffix configuration in the in-history test harness. The assembly override and all admission assertions remain unchanged; this fixes the typed build integration rather than weakening the tests.

packages/core/agent-loop/tests/system-prompt-admission.spec.ts

@@ -21,7 +21,7 @@ async function harness(capable = new MockAdapter(Array.from({ length: 8 }, () =>
   await ctx.plugin(LlmRuntime)
   await ctx.plugin(SessionStore)
   await ctx.plugin(SessionProjectionRegistry)
-  await ctx.plugin(SystemPrompt, { persona: '' })
+  await ctx.plugin(SystemPrompt, { personaPrefix: '', personaSuffix: '' })
   await ctx.plugin(ToolRuntime)
   await ctx.plugin(AgentRegistry)
   await ctx.plugin(AgentLoop, { agents: [] })