shell: starship + shared aliases for bash and zsh

- .chezmoidata/aliases.yaml: single source for shell-agnostic aliases
- fish 20-aliases.fish -> .tmpl rendered from that data (fish-only
  bits: clipboard detection, q function, interactive eza)
- dot_config/shell/aliases.sh.tmpl: same data for bash/zsh
- dot_bashrc/dot_zshrc: managed rc files with starship init
  (replaces unmanaged flyline/p10k prompts), guarded cargo/atuin/envman

dot_config/fish/conf.d/20-aliases.fish.tmpl

@@ -0,0 +1,40 @@
+# Aliases — generated from .chezmoidata/aliases.yaml (shared with bash/zsh
+# via ~/.config/shell/aliases.sh). Add shell-agnostic aliases in the YAML;
+# fish-only bits live below the generated block.
+{{- range .aliases }}
+
+# {{ .section }}
+{{- range .items }}
+alias {{ .name }} {{ if contains " " .cmd }}'{{ .cmd }}'{{ else }}{{ .cmd }}{{ end }}
+{{- end }}
+{{- end }}
+
+# Clipboard
+if command -v wl-copy >/dev/null 2>&1
+    alias cpy wl-copy
+    alias pst wl-paste
+else if command -v pbcopy >/dev/null 2>&1
+    alias cpy pbcopy
+    alias pst pbpaste
+end
+
+# q exits the shell; if this shell was spawned from yazi's own `q` bind
+# (`shell "$SHELL" --block`), also tell that yazi to quit so exiting
+# doesn't bounce back into the file manager.
+function q --description 'exit (and quit parent yazi)'
+    if set -q YAZI_ID; and command -q ya
+        ya emit quit 2>/dev/null
+    end
+    exit
+end
+
+# Interactive-only: don't override `ls` for scripts.
+if status is-interactive
+    # `clear` is functions/clear.fish (kitty scrollback + bottom-pinned
+    # prompt) — don't alias it here, an alias would shadow the autoload.
+    alias celar clear
+    alias claer clear
+    if command -v eza >/dev/null 2>&1
+        alias ls 'eza --icons'
+    end
+end