feat(examples): add jwks_only.rb (LICENSECHAIN_* env)

- README license JWT section + examples list

Author: VoxHash

README.md

@@ -430,13 +430,18 @@ rspec spec/client_spec.rb
 rspec spec/integration/
 ```
 
+## License assertion JWT (RS256 + JWKS)
+
+When Core API returns **`license_token`** and **`license_jwks_uri`**, verify offline with **`LicenseChain::LicenseAssertion.verify_license_assertion_jwt`** (`jwt` gem + JWKS fetch; claim **`token_use`** = **`licensechain_license_v1`**). A minimal **JWKS-only** CLI (no prior `verify` call in-process) is **[`examples/jwks_only.rb`](examples/jwks_only.rb)** — set **`LICENSECHAIN_LICENSE_TOKEN`** and **`LICENSECHAIN_LICENSE_JWKS_URI`** (optional **`LICENSECHAIN_EXPECTED_APP_ID`**), then `ruby examples/jwks_only.rb` (same env names as Go/Rust/PHP; [JWKS_EXAMPLE_PRIORITY](https://github.com/LicenseChain/sdks/blob/main/docs/JWKS_EXAMPLE_PRIORITY.md)).
+
 ## 📝 Examples
 
 See the `examples/` directory for complete examples:
 
 - `basic_usage.rb` - Basic SDK usage
 - `advanced_features.rb` - Advanced features and configuration
 - `webhook_integration.rb` - Webhook handling
+- `jwks_only.rb` — RS256 `license_token` via JWKS only ([JWKS_EXAMPLE_PRIORITY](https://github.com/LicenseChain/sdks/blob/main/docs/JWKS_EXAMPLE_PRIORITY.md))
 
 ## 🤝 Contributing
 
@@ -471,19 +476,19 @@ This project is licensed under the MIT License - see the [LICENSE](LICENSE) file
 ---
 
 **Made with ❤️ for the Ruby community**
-
-## LicenseChain API (v1)
-
-This SDK targets the **LicenseChain HTTP API v1** implemented by the open-source API service.
-
-- **Production base URL:** https://api.licensechain.app/v1
-- **API repository (source of routes & behavior):** https://github.com/LicenseChain/api
-- **Baseline REST mapping (documented for integrators):**
-  - GET /health
-  - POST /auth/register
-  - POST /licenses/verify
-  - PATCH /licenses/:id/revoke
-  - PATCH /licenses/:id/activate
-  - PATCH /licenses/:id/extend
-  - GET /analytics/stats
-
+
+## LicenseChain API (v1)
+
+This SDK targets the **LicenseChain HTTP API v1** implemented by the open-source API service.
+
+- **Production base URL:** https://api.licensechain.app/v1
+- **API repository (source of routes & behavior):** https://github.com/LicenseChain/api
+- **Baseline REST mapping (documented for integrators):**
+  - GET /health
+  - POST /auth/register
+  - POST /licenses/verify
+  - PATCH /licenses/:id/revoke
+  - PATCH /licenses/:id/activate
+  - PATCH /licenses/:id/extend
+  - GET /analytics/stats
+

examples/jwks_only.rb

@@ -0,0 +1,25 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# JWKS-only: verify license_token with token + JWKS URI (parity with Go/Rust/PHP jwks_only).
+#   export LICENSECHAIN_LICENSE_TOKEN="eyJ..."
+#   export LICENSECHAIN_LICENSE_JWKS_URI="https://api.licensechain.app/v1/licenses/jwks"
+#   # optional: LICENSECHAIN_EXPECTED_APP_ID=<uuid>
+#   ruby examples/jwks_only.rb
+
+require 'json'
+require_relative '../lib/licensechain_ruby_sdk'
+
+token = ENV.fetch('LICENSECHAIN_LICENSE_TOKEN', '').strip
+jwks = ENV.fetch('LICENSECHAIN_LICENSE_JWKS_URI', '').strip
+if token.empty? || jwks.empty?
+  warn 'Set LICENSECHAIN_LICENSE_TOKEN and LICENSECHAIN_LICENSE_JWKS_URI'
+  exit 1
+end
+
+opts = {}
+app = ENV['LICENSECHAIN_EXPECTED_APP_ID']&.strip
+opts[:expected_app_id] = app unless app.nil? || app.empty?
+
+payload = LicenseChain::LicenseAssertion.verify_license_assertion_jwt(token, jwks, **opts)
+puts JSON.pretty_generate(payload)