refactor(tmux): combine sesh scripts into single bash script

Replace sesh-gum.sh and sesh-tmux.fish with a unified sesh.sh that
cascades through available tools: gum, fzf-tmux, fzf, bash select.
Falls back to native tmux choose-tree if sesh is not installed.

config/tmux/sesh-gum.sh

@@ -1,18 +0,0 @@
-#!/usr/bin/env bash
-
-# Get session list and pipe it to gum for selection
-SESH_LIST=$(
-  sesh list -i \
-    | gum filter \
-      --limit 1 \
-      --no-sort \
-      --fuzzy \
-      --placeholder 'Pick a sesh' \
-      --height 50 \
-      --prompt='⚡'
-)
-
-# If a session was selected, connect to it
-if [ "$SESH_LIST" != "" ]; then
-  sesh connect "$SESH_LIST"
-fi

config/tmux/sesh-tmux.fish

@@ -1,18 +0,0 @@
-#!/usr/bin/env fish
-
-set selection (sesh list --icons | fzf-tmux -p 80%,70% \
-    --no-sort --ansi --border-label ' sesh ' --prompt '⚡  ' \
-    --header '  ^a all ^t tmux ^g configs ^x zoxide ^d tmux kill ^f find' \
-    --bind 'tab:down,btab:up' \
-    --bind 'ctrl-a:change-prompt(⚡  )+reload(sesh list --icons)' \
-    --bind 'ctrl-t:change-prompt(🪟  )+reload(sesh list -t --icons)' \
-    --bind 'ctrl-g:change-prompt(⚙️  )+reload(sesh list -c --icons)' \
-    --bind 'ctrl-x:change-prompt(📁  )+reload(sesh list -z --icons)' \
-    --bind 'ctrl-f:change-prompt(🔎  )+reload(fd -H -d 2 -t d -E .Trash . ~)' \
-    --bind 'ctrl-d:execute(tmux kill-session -t {2..})+change-prompt(⚡  )+reload(sesh list --icons)' \
-    --preview-window 'right:55%' \
-    --preview 'sesh preview {}')
-
-if test -n "$selection"
-    sesh connect "$selection"
-end

config/tmux/sesh.sh

@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+# Unified sesh session picker with cascading tool detection:
+#   1. gum       — simple fuzzy filter
+#   2. fzf-tmux  — rich UI with keybinds, preview, session kill
+#   3. fzf       — same as fzf-tmux but inline
+#   4. select    — bare minimum numbered menu
+
+set -euo pipefail
+
+# Fall back to native tmux session picker if sesh is not installed
+if ! command -v sesh &>/dev/null; then
+  tmux choose-tree -Zs
+  exit 0
+fi
+
+pick_with_gum() {
+  sesh list -i \
+    | gum filter \
+      --limit 1 \
+      --no-sort \
+      --fuzzy \
+      --placeholder 'Pick a sesh' \
+      --height 50 \
+      --prompt='⚡'
+}
+
+FZF_COMMON_OPTS=(
+  --no-sort --ansi
+  --border-label ' sesh '
+  --prompt '⚡  '
+  --header '  ^a all ^t tmux ^g configs ^x zoxide ^d tmux kill ^f find'
+  --bind 'tab:down,btab:up'
+  --bind 'ctrl-a:change-prompt(⚡  )+reload(sesh list --icons)'
+  --bind 'ctrl-t:change-prompt(🪟  )+reload(sesh list -t --icons)'
+  --bind 'ctrl-g:change-prompt(⚙️  )+reload(sesh list -c --icons)'
+  --bind 'ctrl-x:change-prompt(📁  )+reload(sesh list -z --icons)'
+  --bind 'ctrl-f:change-prompt(🔎  )+reload(fd -H -d 2 -t d -E .Trash . ~)'
+  --bind 'ctrl-d:execute(tmux kill-session -t {2..})+change-prompt(⚡  )+reload(sesh list --icons)'
+  --preview-window 'right:55%'
+  --preview 'sesh preview {}'
+)
+
+pick_with_fzf_tmux() {
+  sesh list --icons | fzf-tmux -p 80%,70% "${FZF_COMMON_OPTS[@]}"
+}
+
+pick_with_fzf() {
+  sesh list --icons | fzf "${FZF_COMMON_OPTS[@]}"
+}
+
+pick_with_select() {
+  local sessions
+  mapfile -t sessions < <(sesh list)
+  if [[ ${#sessions[@]} -eq 0 ]]; then
+    return
+  fi
+  PS3="Select session: "
+  select choice in "${sessions[@]}"; do
+    if [[ -n "${choice-}" ]]; then
+      printf '%s' "$choice"
+      break
+    fi
+  done
+}
+
+# Cascading tool detection
+if command -v gum &>/dev/null; then
+  selection=$(pick_with_gum)
+elif command -v fzf-tmux &>/dev/null; then
+  selection=$(pick_with_fzf_tmux)
+elif command -v fzf &>/dev/null; then
+  selection=$(pick_with_fzf)
+else
+  selection=$(pick_with_select)
+fi
+
+if [[ -n "${selection-}" ]]; then
+  sesh connect "$selection"
+fi

config/tmux/tmux.conf

@@ -89,7 +89,7 @@ bind C-p previous-window
 bind C-n next-window
 
 # global sessions
-bind -N "sesh selection"           t display-popup -E "$HOME/.dotfiles/config/tmux/sesh-gum.sh"
+bind -N "sesh selection"           t display-popup -E "$HOME/.dotfiles/config/tmux/sesh.sh"
 bind -N "last-session (via sesh) " L run-shell "sesh last"
 bind -N "sesh ui"                  N display-popup -E "sesh ui"