fix(agent): preserve in-process MCP server across session refresh

[tatoalo]

Problem

in cloud runs, the agent's only push path is the in-process git_signed_commit / git_signed_rewrite tool, those tools are served by an in-process MCP server, posthog-code-tools, registered once in createSession.

refreshSession silently evicted posthog-code-tools for the rest of the session. Once that happened, the agent's next git_signed_commit failed with "No such tool available" and lost its only way to commit/push.

Fix

when assembling the refreshed query options, carry over any type: "sdk" server from the previous options and merge it last (so the managed in-process server can never be shadowed by a refresh entry)

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 2ffccbd.}

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix(agent): preserve in-process MCP serv..." | Re-trigger Greptile}