chore: expand .gitignore with credential and secret patterns

.gitignore

@@ -2,4 +2,56 @@
 *.tgz
 .vscode
 .idea
-.DS_Store
+.DS_Store
+*.swp
+
+# Credentials and secrets
+.git-credentials
+.netrc
+._netrc
+.vault-token
+aws-config.json
+aws-secret.yaml
+.aws/
+application_default_credentials.json
+*-service-account-key.json
+*-sa-key.json
+service-account*.json
+*.dec.yaml
+*.pem
+*.key
+*.age
+id_rsa
+id_rsa.pub
+id_dsa
+id_dsa.pub
+id_ecdsa
+id_ecdsa.pub
+id_ed25519
+id_ed25519.pub
+.keys/
+secrets/
+!secrets/.gitkeep
+*creds*
+*password*
+client_secret.json
+client_secrets.json
+credentials.json
+google-services.json
+*.jks
+*.keystore
+
+# Environment files
+.env
+.env.*
+!.env.example
+!.env.template
+!.env.sample
+.envrc
+*.env
+
+# Kubeconfig
+kubeconfig_*
+
+# Claude Code
+.claude/