docs(zinit): fix bpick pattern and recommend wait/lucid for zinit installation

[HaleTom]

The zinit installation docs at https://docs.atuin.sh/cli/guide/installation/ have two issues:

1. bpick pattern matches server binary

The current pattern bpick"atuin-*.tar.gz" matches both the client binary (atuin-x86_64-unknown-linux-gnu.tar.gz) and the server binary (atuin-server-x86_64-unknown-linux-gnu.tar.gz). Since GitHub releases returns the server asset first alphabetically, users get the wrong binary:

[ziextract] Unpacking the files from: `atuin-server-x86_64-unknown-linux-gnu.tar.gz'...
Warning: mv ice didn't match any file. [atuin*/atuin -> atuin]
Available files: atuin-server-x86_64-unknown-linux-gnu
(eval):1: no such file or directory: ./atuin

Fix: Use zsh glob exclusion to skip server artifacts:

-bpick"atuin-*.tar.gz"
+bpick"atuin-*.tar.gz~*server*"

2. Missing wait and lucid ices

The current zinit example loads synchronously during .zshrc processing. For a binary plugin that doesn't need to be available until after the prompt, wait (turbo mode) and lucid (suppress "Loaded" message) are recommended:

-zinit ice as"command" from"gh-r" bpick"atuin-*.tar.gz" mv"atuin*/atuin -> atuin" \
+zinit ice wait lucid as"command" from"gh-r" bpick"atuin-*.tar.gz~*server*" mv"atuin*/atuin -> atuin" \

Proposed corrected example

zinit ice wait lucid as"command" from"gh-r" bpick"atuin-*.tar.gz~*server*" mv"atuin*/atuin -> atuin" \
    atclone"./atuin init zsh > init.zsh; ./atuin gen-completions --shell zsh > _atuin" \
    atpull"%atclone" src"init.zsh"
zinit light atuinsh/atuin

This matches the pattern used by other zinit-installed CLI tools (zoxide, fd, etc.) on the zinit wiki.