Make taste global by default to support Git worktrees

Feature Description

Currently taste is stored per worktree, so it’s not shared when using git worktree. Please make taste global by default

Use Case

I work with multiple worktrees across branches and need the same taste everywhere. Global taste avoids separate setups and missing data in each worktree, making the workflow smooth.

Additional Context

No response

How important is this to you?

Nice to have

首先，追踪 taste 当前按每个 worktree 存储的位置，以及该命令如何识别 Git worktree。在更改默认作用域之前，检查现有的持久化和配置行为。完成的标准是：taste 默认在 repository 的各个 worktree 之间共享，并且当前用例无需单独设置即可运行。