feat: replace gum with fzf, add delete and PR preview

- Replace all gum usage with fzf for TUI interactions
- Add ANSI color helper functions for styling
- Add 'd' key to delete worktrees with confirmation modal
- Add PR preview pane showing `gh pr view` output
- Add file-based caching for PR previews
- Use fzf --style=full for enhanced styling
- Change required dependency from gum to fzf

Co-Authored-By: Claude Code (User Settings, in: ${CLAUDE_PROJECT_DIR}) <noreply@anthropic.com>

Author: nsheaps

bin/git-wt

@@ -49,6 +49,15 @@ get_version() {
 SCAN_DIR="${HOME}/src"
 TARGET_BRANCH=""
 UPDATE_CHECK_FILE="/tmp/git-wt-update-check-$$"
+PR_CACHE_DIR="/tmp/git-wt-pr-cache-$$"
+export PR_CACHE_DIR  # Export for fzf preview subshell
+
+# ANSI color helpers (defined early for use in exit trap)
+style_bold() { printf '\033[1m%s\033[0m\n' "$1"; }
+style_warn() { printf '\033[38;5;214m%s\033[0m\n' "$1"; }
+style_error() { printf '\033[38;5;196m%s\033[0m\n' "$1"; }
+style_success() { printf '\033[38;5;82m%s\033[0m\n' "$1"; }
+style_bold_error() { printf '\033[1;38;5;196m%s\033[0m\n' "$1"; }
 
 # Background update check - runs asynchronously
 check_for_updates() {
@@ -84,7 +93,10 @@ check_for_updates "$CURRENT_VERSION" &
 UPDATE_CHECK_PID=$!
 
 # Cleanup and show update notification on exit
-show_update_notification() {
+cleanup_and_notify() {
+  # Cleanup PR cache directory
+  rm -rf "$PR_CACHE_DIR" 2>/dev/null || true
+
   # Wait briefly for background check (non-blocking if already done)
   wait "$UPDATE_CHECK_PID" 2>/dev/null || true
 
@@ -97,12 +109,12 @@ show_update_notification() {
     if [[ "$update_info" == UPDATE_AVAILABLE=* ]]; then
       local new_version="${update_info#UPDATE_AVAILABLE=}"
       echo ""
-      gum style --foreground 214 "A new release of git-wt is available: ${CURRENT_VERSION#v} → $new_version"
+      style_warn "A new release of git-wt is available: ${CURRENT_VERSION#v} → $new_version"
       echo "To upgrade, run: brew upgrade git-wt"
     fi
   fi
 }
-trap show_update_notification EXIT
+trap cleanup_and_notify EXIT
 
 show_help() {
   sed -n '2,17p' "$0" | sed 's/^# //' | sed 's/^#//'
@@ -124,15 +136,31 @@ check_tool() {
   if ! command -v "$1" &>/dev/null; then
     echo "Error: $1 is required but not installed" >&2
     case "$1" in
-      gum) echo "Install with: brew install gum" >&2 ;;
+      fzf) echo "Install with: brew install fzf" >&2 ;;
     esac
     exit 1
   fi
 }
 
-check_tool gum
+check_tool fzf
 check_tool git
 
+# Confirm prompt (returns 0 for yes, 1 for no)
+confirm() {
+  local prompt="${1:-Confirm?}"
+  local result
+  result=$(printf 'Yes\nNo' | fzf --header="$prompt" --height=5 --no-info)
+  [[ "$result" == "Yes" ]]
+}
+
+# Text input prompt
+input_prompt() {
+  local placeholder="${1:-Enter value}"
+  local result
+  result=$(fzf --print-query --header="$placeholder" --height=3 --no-info < /dev/null 2>/dev/null | head -1)
+  echo "$result"
+}
+
 # Function to find repos in a directory
 find_repos_in_dir() {
   local dir="$1"
@@ -148,11 +176,10 @@ select_repo() {
   local repos=()
 
   echo ""
-  gum style --bold "Not in a git repository"
+  style_bold "Not in a git repository"
   echo ""
 
-  echo ""
-  gum spin --title "Scanning $SCAN_DIR for git repos..." -- sleep 0.5
+  echo "Scanning $SCAN_DIR for git repos..."
 
   # Find repos
   while IFS= read -r repo_path; do
@@ -167,7 +194,7 @@ select_repo() {
   fi
 
   # Let user select
-  SELECTED_REPO=$(printf '%s\n' "${repos[@]}" | gum filter --placeholder "Select repository...")
+  SELECTED_REPO=$(printf '%s\n' "${repos[@]}" | fzf --prompt="Select repository> ")
   if [[ -z "$SELECTED_REPO" ]]; then
     echo "Cancelled"
     exit 0
@@ -239,11 +266,11 @@ switch_to_branch() {
 
     # Ask what to base it on
     local base_options=("$default_branch (default)" "other...")
-    local base_selected=$(printf '%s\n' "${base_options[@]}" | gum choose --header "Create new branch based on:")
+    local base_selected=$(printf '%s\n' "${base_options[@]}" | fzf --header="Create new branch based on:" --height=5 --no-info)
 
     local base_branch="$default_branch"
     if [[ "$base_selected" == "other..."* ]]; then
-      base_branch=$(git -C "$git_root" branch -a --format='%(refname:short)' | gum filter --placeholder "Select base branch...")
+      base_branch=$(git -C "$git_root" branch -a --format='%(refname:short)' | fzf --prompt="Select base branch> ")
     fi
 
     git -C "$git_root" worktree add -b "$branch" "$worktree_path" "$base_branch"
@@ -289,12 +316,17 @@ fi
 
 # Fetch from remote first
 echo ""
-gum spin --title "Fetching from remote..." -- git -C "$GIT_ROOT" fetch origin --prune 2>/dev/null || true
+echo "Fetching from remote..."
+git -C "$GIT_ROOT" fetch origin --prune 2>/dev/null || true
+
+# Setup for PR preview caching
+mkdir -p "$PR_CACHE_DIR"
+export GIT_ROOT  # Export for fzf preview subshell
 
 # If branch specified, directly create/switch to that worktree
 if [[ -n "$TARGET_BRANCH" ]]; then
   echo ""
-  gum style --bold "Switching to worktree for: $TARGET_BRANCH"
+  style_bold "Switching to worktree for: $TARGET_BRANCH"
   echo ""
 
   switch_to_branch "$TARGET_BRANCH" "$GIT_ROOT"
@@ -303,7 +335,7 @@ fi
 
 # Interactive mode - offer worktree selection
 echo ""
-gum style --bold "Git Worktree Selector"
+style_bold "Git Worktree Selector"
 echo ""
 
 # Get existing worktrees (including root checkout) and track their branches
@@ -358,19 +390,103 @@ done
 # Add option to switch repo (step "up")
 MENU_OPTIONS+=("🔄 (switch repository)")
 
-# Show selection menu (--no-sort keeps existing worktrees at top while filtering)
-SELECTED=$(printf '%s\n' "${MENU_OPTIONS[@]}" | gum filter --no-sort --placeholder "Select or create worktree...")
+# Show selection menu with fzf
+# Preview shows PR info from cache, falls back to single fetch if not cached yet
+KEY_PRESSED=""
+FZF_RESULT=$(printf '%s\n' "${MENU_OPTIONS[@]}" | fzf \
+  --style=full \
+  --expect=d \
+  --no-sort \
+  --header="enter=select, d=delete worktree" \
+  --prompt="Select or create worktree> " \
+  --preview='
+    item={}
+    # Extract branch name from different formats
+    if [[ "$item" == "📂 [worktree]"* ]] || [[ "$item" == "🏠 [root]"* ]]; then
+      branch=$(echo "$item" | sed "s/^[^ ]* \[[^]]*\] //" | sed "s/ →.*//")
+    elif [[ "$item" == "📁"* ]] || [[ "$item" == "🔄"* ]]; then
+      echo "No preview available"
+      exit 0
+    else
+      branch="$item"
+    fi
+
+    # Read from cache if available
+    safe_branch=$(echo "$branch" | tr "/" "_")
+    cache_file="$PR_CACHE_DIR/$safe_branch"
+
+    if [[ -f "$cache_file" ]]; then
+      cat "$cache_file"
+    elif command -v gh &>/dev/null; then
+      # Cache miss - fetch just this branch from correct repo context
+      cd "$GIT_ROOT" 2>/dev/null || true
+      result=$(gh pr view "$branch" 2>&1)
+      if [[ $? -eq 0 ]]; then
+        echo "$result" | tee "$cache_file"
+      else
+        echo "No PR found for branch: $branch" | tee "$cache_file"
+      fi
+    else
+      echo "No PR found for branch: $branch"
+    fi
+  ' \
+  --preview-window=right:50%:wrap)
+KEY_PRESSED=$(echo "$FZF_RESULT" | head -1)
+SELECTED=$(echo "$FZF_RESULT" | tail -1)
 
 if [[ -z "$SELECTED" ]]; then
   echo "Cancelled"
   exit 0
 fi
 
+# Handle 'd' key press for delete
+if [[ "$KEY_PRESSED" == "d" ]]; then
+  # Only allow deleting worktrees (not root, not create option, not branches)
+  if [[ "$SELECTED" != "📂 [worktree]"* ]]; then
+    echo ""
+    style_warn "Cannot delete: only worktrees can be deleted with 'd'"
+    echo "Selected item: $SELECTED"
+    exit 1
+  fi
+
+  # Extract worktree path
+  WT_PATH=$(echo "$SELECTED" | sed 's/.*→ //')
+  WT_BRANCH=$(echo "$SELECTED" | sed 's/📂 \[worktree\] //' | sed 's/ →.*//')
+
+  echo ""
+  style_bold_error "Delete Worktree"
+  echo ""
+  echo "Branch: $WT_BRANCH"
+  echo "Path: $WT_PATH"
+  echo ""
+
+  if confirm "Are you sure you want to delete this worktree?"; then
+    # Remove the worktree
+    if git -C "$GIT_ROOT" worktree remove "$WT_PATH" 2>/dev/null; then
+      echo ""
+      style_success "✓ Worktree deleted successfully"
+    else
+      # Try force remove if normal remove fails
+      echo ""
+      style_warn "Worktree has uncommitted changes or other issues."
+      if confirm "Force delete? (will discard any uncommitted changes)"; then
+        git -C "$GIT_ROOT" worktree remove --force "$WT_PATH"
+        style_success "✓ Worktree force deleted"
+      else
+        echo "Cancelled"
+      fi
+    fi
+  else
+    echo "Cancelled"
+  fi
+  exit 0
+fi
+
 # Handle selection
 case "$SELECTED" in
   "📁 (create new worktree)")
     # Get branch name
-    BRANCH_NAME=$(gum input --placeholder "Enter new branch name...")
+    BRANCH_NAME=$(input_prompt "Enter new branch name")
     if [[ -z "$BRANCH_NAME" ]]; then
       echo "Cancelled"
       exit 0
@@ -381,12 +497,12 @@ case "$SELECTED" in
     DEFAULT_BRANCH=$(git -C "$GIT_ROOT" symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's@^refs/remotes/origin/@@' || echo "main")
 
     BASE_OPTIONS=("$DEFAULT_BRANCH (default)" "$CURRENT_BRANCH (current)" "other...")
-    BASE_SELECTED=$(printf '%s\n' "${BASE_OPTIONS[@]}" | gum choose --header "Base branch:")
+    BASE_SELECTED=$(printf '%s\n' "${BASE_OPTIONS[@]}" | fzf --header="Base branch:" --height=6 --no-info)
 
     case "$BASE_SELECTED" in
       *"(default)"*) BASE_BRANCH="$DEFAULT_BRANCH" ;;
       *"(current)"*) BASE_BRANCH="$CURRENT_BRANCH" ;;
-      *) BASE_BRANCH=$(git -C "$GIT_ROOT" branch -a --format='%(refname:short)' | gum filter --placeholder "Select base branch...") ;;
+      *) BASE_BRANCH=$(git -C "$GIT_ROOT" branch -a --format='%(refname:short)' | fzf --prompt="Select base branch> ") ;;
     esac
 
     # Create worktree path