[Feature]: "Restart thread" action to reload provider config (MCP servers, etc.) while keeping conversation context #5437

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

Not sure

Problem

Provider config changes (e.g. adding or editing an MCP server) only take effect on a fresh provider session. In the Claude Code terminal the workflow is trivial: exit the session and run claude --continue to reload configs while keeping the full conversation. In T3 Code (web and mobile) there is no equivalent — the only option is starting a brand-new thread and losing all context.

Proposal

A per-thread "Restart session" action that tears down the provider process and resumes the same conversation (e.g. via the provider's native resume/continue mechanism, like claude --continue / Codex resume), picking up the current MCP/config state.

Scope

Deliberately small: no config editing UI, just a restart-and-resume action on an existing thread.