[FEATURE] Rename Spark/Conversation Title in VSCode Extension

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Currently, conversation titles (sparks) in the VSCode extension are automatically generated from the first words of the conversation. This leads to many conversations with unhelpful titles like "Salut", "Hello", "Hey", etc., making it difficult to identify and find past conversations.

Proposed Solution

Add the ability to rename sparks directly in the VSCode extension, similar to the /rename command available in the CLI version.

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

Organize conversations by topic or feature (e.g., "auth-refactor", "bug-fix-login", "api-integration")
Quickly find relevant past conversations
Maintain a clean and navigable conversation history

Additional Context

<img width="388" height="281" alt="Image" src="https://github.com/user-attachments/assets/a05166d1-c262-4682-b034-6aeffa316a13" />