Add interactive fuzzy finding support

[tobiase]

Overview

Add fuzzy finding for better UX when selecting worktrees.

Features

Interactive worktree selection

$ wt go --fuzzy
> Select worktree:
  main
> fea|
  feature-1
  feature-2
  feature-login

Interactive project command selection

$ wt --fuzzy
> Select command:
  list
  add
  go
> das|
  dash

Implementation options

1. Build simple selector in Go
2. Optional dependency on fzf if available
3. Fall back to numbered selection

Acceptance criteria

• Works without external dependencies
• Supports arrow keys and vim bindings
• Filters as you type
• Shows preview (branch info)

[tobiase]

Fuzzy finding support has been fully implemented. The codebase now includes:

• / flags available for all major commands (go, rm, env, etc.)
• Interactive selector in using
• Arrow keys and vim bindings support
• Real-time filtering as you type
• Works without external dependencies (fallback to numbered selection)

All acceptance criteria from this issue have been met.