Feature: allow agent to rename the current session/conversation

Problem

When working with multiple Claude Code sessions in parallel (e.g., several VSCode windows with different tasks), the session/conversation title is auto-generated from the first few words of the user's initial message. This often results in unhelpful titles like "User Username reported..." that don't convey the actual task being worked on.

The user has to mentally map each window to its task, which becomes painful with 3-5+ concurrent sessions.

Proposed solution

Provide a tool (or built-in capability) that allows the agent to rename the current session. The agent could automatically set a meaningful title after understanding the task scope — e.g., "IMA-120: fix instruction text" instead of the first words of the message.

Suggested API:

• A new tool like RenameSession or SetSessionTitle with a title parameter
• Or a slash command like /rename <title>

When the agent would use it:

• After understanding the task scope (typically after the first exchange)
• When the task scope changes significantly mid-session

Use case

Power users running multiple parallel agent sessions need to quickly identify which window handles which task. A descriptive title set by the agent (who understands the task context) would solve this immediately.

Current workaround

Starting the first message with a descriptive prefix (e.g., "IMA-120: fix instructions"). This works but requires discipline and doesn't help when the task evolves.