feat(zsh): add Alt-Shift-Y widget to copy last command output

Zellij has no native "copy last command output" feature, and ghostty's
jump_to_prompt (Ctrl+Shift+J/K, via OSC 133) can't work inside zellij
because zellij sits between the shell and the terminal emulator.

Build it ourselves: a zle widget runs 'zellij action dump-screen --full',
finds the last two lines matching the prompt prefix (user@host:), and
pipes everything between them to wl-copy. Bound to Alt+Shift+Y.

Requires running inside zellij and at least two prompts in the scrollback.

1 files changed, 39 insertions, 0 deletions

diff --git a/dot_config/zsh/dot_zshrc b/dot_config/zsh/dot_zshrc
index c7d5e90..db9fa85 100644
--- a/dot_config/zsh/dot_zshrc
+++ b/dot_config/zsh/dot_zshrc
@@ -241,6 +241,45 @@ alias sub='subliminal download -l en'
 # Use `| wlc` to copy AND see the output.
 wlc() { tee >(wl-copy "$@"); }
 
+# Copy the *last* command's output to the clipboard, retroactively.
+# Works only inside zellij — uses `zellij action dump-screen --full` and
+# locates prompt boundaries by matching the prompt prefix `user@host:`.
+# Bound to Alt+Shift+Y as a zle widget.
+copy-last-output() {
+	emulate -L zsh
+	if [[ -z $ZELLIJ ]]; then
+		zle -M "copy-last-output: not inside a zellij session"
+		return 1
+	fi
+	local dump
+	dump=$(zellij action dump-screen --full 2>/dev/null) || {
+		zle -M "copy-last-output: dump-screen failed"
+		return 1
+	}
+	local prompt_re='^[[:alnum:]_-]+@[[:alnum:]_-]+:'
+	local -a lines
+	lines=("${(@f)dump}")
+	local -a prompt_idx
+	local i
+	for (( i = 1; i <= ${#lines}; i++ )); do
+		[[ ${lines[i]} =~ $prompt_re ]] && prompt_idx+=($i)
+	done
+	if (( ${#prompt_idx} < 2 )); then
+		zle -M "copy-last-output: need at least 2 prompts in scrollback"
+		return 1
+	fi
+	local start=$(( ${prompt_idx[-2]} + 1 ))
+	local end=$(( ${prompt_idx[-1]} - 1 ))
+	if (( start > end )); then
+		zle -M "copy-last-output: previous command produced no output"
+		return 0
+	fi
+	printf '%s\n' "${lines[start,end]}" | wl-copy
+	zle -M "copied $((end - start + 1)) line(s) of last command output"
+}
+zle -N copy-last-output
+bindkey '^[Y' copy-last-output  # Alt+Shift+Y
+
 # Neovim
 alias n='nvim'
 alias ndiff='nvim -d'