Allow custom worktree naming convention when auto-creating worktrees on session start

When starting a new session in the Claude Code desktop app, a worktree is automatically created with a random name (e.g., sharp-buck, eloquent-darwin). These names make it difficult to identify which worktree corresponds to which task when managing multiple sessions.

It would be helpful to have a setting (in settings.json or project-level .claude/settings.json) that controls the auto-generated worktree name format, or prompts the user for a name before creating it. For example:

• A naming template like wt-{branch} or wt-{date}-{random}
• An option to prompt for a name on session start instead of auto-generating
• A way to define a naming convention in CLAUDE.md that gets applied at creation time

Currently there's no way to intercept or customize the name since the worktree is created before CLAUDE.md instructions are read or any user input is received.