Add git prerequisite checks to migration scripts

- 10-check-git-sync.sh: Check for git before running
- run-migration-analysis.sh: Include git in prerequisite checks
- Fixes script failures when git is not installed

docs/how-to/migration-scripts/10-check-git-sync.sh

@@ -118,6 +118,11 @@ usage() {
 check_prerequisites() {
     local missing=0
     
+    if ! command -v git &> /dev/null; then
+        log_error "git not found. Install with your package manager."
+        missing=1
+    fi
+    
     if ! command -v nak &> /dev/null; then
         log_error "nak not found. Install from: https://github.com/fiatjaf/nak"
         log_error "Or run: nix-shell -p nak jq --run \"$0 $*\""
@@ -161,13 +166,15 @@ count_git_refs() {
         return
     fi
     
-    # Use git show-ref to handle both packed and loose refs
-    # Fall back to counting loose refs if git show-ref fails
-    if git --git-dir="$git_dir" show-ref --heads 2>/dev/null | wc -l | tr -d ' '; then
+    # Try git show-ref first (handles packed refs correctly)
+    # Note: We capture output separately to avoid pipefail issues
+    local count
+    if count=$(git --git-dir="$git_dir" show-ref --heads 2>/dev/null | wc -l); then
+        echo "$count" | tr -d ' '
         return
     fi
     
-    # Fallback: count loose refs
+    # Fallback: count loose refs (when git is not available or fails)
     if [[ -d "$git_dir/refs/heads" ]]; then
         find "$git_dir/refs/heads" -type f 2>/dev/null | wc -l | tr -d ' '
     else

docs/how-to/migration-scripts/run-migration-analysis.sh

@@ -155,7 +155,7 @@ FROM_PHASE=""
 declare -A PHASE_TIMES
 
 usage() {
-    head -80 "$0" | tail -n +3 | sed 's/^# //' | sed 's/^#//'
+    head -73 "$0" | tail -n +3 | sed 's/^# //' | sed 's/^#//'
     exit 0
 }
 
@@ -285,7 +285,7 @@ check_prerequisites() {
     log_info "Checking prerequisites..."
     
     # Required tools
-    for tool in nak jq awk sort; do
+    for tool in git nak jq awk sort; do
         if command -v "$tool" &> /dev/null; then
             log_step "$tool: found"
         else