feat: enhance Git 1Password integration with debugging commands and common issue guidance

docs/git-1password-setup.md

@@ -114,8 +114,31 @@ op signin
 ```bash
 # Test the credential helper directly
 echo -e "protocol=https\nhost=github.com\n" | ~/.dotfiles/scripts/git-credential-1password.sh get
+
+# Debug: List all 1Password items to see what's available
+op item list --format=json | jq -r '.[] | "\(.title) - \(.id)"'
+
+# Debug: See the structure of a specific item
+op item get "YOUR_ITEM_ID" --format=json | jq
+
+# Debug: Check what fields are available in an item
+op item get "YOUR_ITEM_ID" --format=json | jq -r '.fields[] | "\(.label // .id): \(.value // "empty")"'
 ```
 
+### Common Issues
+
+**jq null matching errors:**
+
+- This happens when 1Password items have missing fields
+- The updated script handles null values gracefully
+- Make sure your items have proper username and password fields
+
+**Field naming issues:**
+
+- The script looks for fields with labels containing: "username", "user", "login"
+- For passwords, it looks for: "password", "token", "secret", "pass"
+- If your fields have different names, rename them in 1Password
+
 ## Security Benefits
 
 - Credentials are never stored in plain text on disk