feat(worktree): unify /worktree with add/list/switch/delete subcommands and inline menu

[kamysheblid]

Summary

This PR unifies the command into a consistent subcommand-based interface with inline menu support.

What changed

• Added as the new worktree creation flow
• Unified worktree management under with add/list/switch/delete/help subcommands
• Added inline menu for worktree selection and management
• Added worktree creation flow with project validation and confirmation
• Added i18n support for worktree management across all locales
• Added tests for the worktree service and command behavior

Notes

• The worktree creation flow uses the OpenCode API's endpoint
• Worktree management is now consistent with the rest of the bot's command patterns
• The models toggle feature is intentionally excluded from this PR and will be submitted separately