[FEATURE] Allow A ClaudeCode-Per-Tab

## Feature Description
`:ClaudeCode` appears to only work in the current tab. This is somewhere between a bug and a feature request but basically people should be able to make at least one Window of ClaudeCode per-tab.

```vim
:tabnew
:ClaudeCode
:tabnew
:ClaudeCode
```
(Creates 2 separate windows)

Currently if you try to Neovim tabs give a different view for buffers (e.g. `:tabnew`). Currently if you call `:ClaudeCode`, it
A clear and concise description of what you'd like to see added to the plugin.

## Use Case

Though I'd love to just use tmux, it's not always available. When that happens, I use Neovim tabs.

And just in general being able to have more than one Claude Code open in a single Neovim instance would be generally useful

## Proposed Solution

If a new command like `:ClaudeCodeFromThisWindow` or something was created, I could manage the windows myself programmatically.

## Alternatives Considered

Possibly related: https://github.com/coder/claudecode.nvim/issues/187

Commencez par la commande :ClaudeCode et comparez son comportement dans les exemples de :tabnew de cet issue, puis examinez l’issue 187 associée. C’est terminé lorsque des onglets Neovim distincts peuvent chacun créer et gérer une fenêtre Claude Code indépendante, soit via des appels répétés à :ClaudeCode, soit au moyen d’une commande telle que :ClaudeCodeFromThisWindow.

Rédigé par le modèle d'indexation à partir du texte de l'issue.