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_bashrc

@@ -0,0 +1,24 @@
+#
+# ~/.bashrc — managed by chezmoi
+#
+
+# If not running interactively, don't do anything
+[[ $- != *i* ]] && return
+
+# PATH extras / tool envs (machine-optional, guarded)
+[ -f "$HOME/.cargo/env" ] && . "$HOME/.cargo/env"
+[ -d "$HOME/.maestro/bin" ] && PATH="$PATH:$HOME/.maestro/bin"
+
+# Shared aliases (same set as fish/zsh; source of truth: .chezmoidata/aliases.yaml)
+[ -f "$HOME/.config/shell/aliases.sh" ] && . "$HOME/.config/shell/aliases.sh"
+
+# atuin shell history (needs bash-preexec)
+[ -f "$HOME/.atuin/bin/env" ] && . "$HOME/.atuin/bin/env"
+[ -f "$HOME/.bash-preexec.sh" ] && . "$HOME/.bash-preexec.sh"
+command -v atuin >/dev/null 2>&1 && eval "$(atuin init bash)"
+
+# Generated for envman. Do not edit.
+[ -s "$HOME/.config/envman/load.sh" ] && . "$HOME/.config/envman/load.sh"
+
+# Prompt — starship, consistent with fish
+command -v starship >/dev/null 2>&1 && eval "$(starship init bash)"