refactor(fish): use command -q, group aliases, add mise config

- Replace test -x / command -qv with command -q for consistency
- Move mise/direnv/zoxide/fzf init to top of interactive block
- Group related aliases into if blocks
- Remove redundant vim/vi->v aliases (nvim handles EDITOR)
- Fix fabric alias: fabric-ai -> fabric
- Add config/mise/config.toml with tool definitions
- Swap realpath/nvim check order in script/v

script/v

@@ -1,6 +1,6 @@
 #!/usr/bin/env sh
 
-required_tools=(nvim realpath)
+required_tools=(realpath nvim)
 missing=()
 
 for tool in "${required_tools[@]}"; do