Improve gp script: fix autocomplete and enhance change detection logic

gp/gp

@@ -131,10 +131,25 @@ check_git_repo() {
 
 # Function to check for uncommitted changes
 check_for_changes() {
-    if git diff --cached --quiet && git diff --quiet; then
-        if [ "$ADD_ALL" = false ]; then
+    local has_staged=$(! git diff --cached --quiet && echo "true" || echo "false")
+    local has_modified=$(! git diff --quiet && echo "true" || echo "false")
+    local has_untracked=$([ -n "$(git ls-files --others --exclude-standard)" ] && echo "true" || echo "false")
+    
+    # If add-all is enabled, check if we have any changes at all
+    if [ "$ADD_ALL" = true ]; then
+        if [ "$has_staged" = false ] && [ "$has_modified" = false ] && [ "$has_untracked" = false ]; then
+            print_info "No changes to commit (working tree clean)"
+            exit 0
+        fi
+    else
+        # If add-all is disabled, only check staged changes
+        if [ "$has_staged" = false ]; then
+            if [ "$has_modified" = true ] || [ "$has_untracked" = true ]; then
                 print_warning "No staged changes found"
                 print_info "Use 'gp -a' to add all files, or stage changes first with 'git add'"
+            else
+                print_info "No changes to commit (working tree clean)"
+            fi
             exit 0
         fi
     fi