[FEATURE] Add Ability to Quickly Mark Chat Sessions as Complete

### Preflight Checklist

- [x] I have searched [existing requests](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20label%3Aenhancement) and this feature hasn't been requested yet
- [x] This is a single feature request (not multiple features)

### Problem Statement

### Preflight Checklist

- [x] I have searched [existing requests](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20label%3Aenhancement) and this feature hasn't been requested yet
- [x] This is a single feature request (not multiple features)

### Problem Statement

**Add a way to mark chat sessions as complete**

I often have projects with many chat sessions, and it can be difficult to distinguish completed sessions from those that are still in progress, especially when working across several sessions at once.

It would be helpful to add a status toggle button next to the existing rename and delete icons that lets users mark a chat session as complete. A checkmark icon or similar visual indicator would toggle the session's status at a glance when clicked.

Ideally, users could:

* Mark a session as complete or in progress
* See the status clearly in the session list
* Reopen or change the status of a completed session
* Keep completed sessions available for future reference

My current workaround is to add emojis to the beginning of session names, such as a checkmark for completed sessions. A built-in status indicator would make this workflow faster and provide a more consistent user experience. I like the use of emojis here because they make the status clear to the user.

I do not want to delete completed sessions because I frequently need to return to them for reference.

### Priority

High - Significant impact on productivity

### Feature Category

Other

### Use Case Example

When the user starts the chat, the session will automatically be assigned a pencil emoji at the start of the title.
User completes the chat as normal and wants to mark the session as complete. User clicks the new checkmark icon, and the emoji at the front of the chat title changes from a pencil to a green checkmark. If the user clicks the icon again, it will revert to the pencil (or cycle through all available emojis)

### Proposed Solution

### Proposed Solution

Add a 3rd button next to the pencil and delete icons (maybe a checkmark) that would toggle the status of the chat and automatically inject the following emojis:

- ✅ Chat session is marked as completed
- ✏️ Chat session is currently in progress and not yet completed
- ⏲️ (optional) Chat session is still in progress, but should be revisited later

### Alternative Solutions

### Alternative Solutions

Adding emojis manually to the beginning of session names works but is tedious. A built-in status indicator would make this workflow faster and provide a more consistent user experience.

### Priority

High - Significant impact on productivity

### Feature Category

Other

### Use Case Example

### Use Case Example

When the user starts the chat, the session will automatically be assigned a pencil emoji at the start of the title.
User completes the chat as normal and wants to mark the session as complete. User clicks the new checkmark icon, and the emoji at the front of the chat title changes from a pencil to a green checkmark. If the user clicks the icon again, it will revert to the pencil (or cycle through all available emojis)

### Additional Context

_No response_

Start by locating the session list and the existing rename and delete actions. Define how completion status is stored and displayed, then verify that users can toggle between complete and in-progress states, reopen completed sessions, and retain them for reference.

Written by the indexing model from the issue text.