Added telemetry Support

[tanya732]

Summary

Adds Auth0-Client telemetry header to JWKS requests made during JWT validation. This enables Auth0 to track SDK usage and version adoption across customer deployments.

Changes

• New TelemetryProvider class — Builds and caches a Base64url-encoded JSON payload containing the SDK name, version, and Java runtime version.
• New auth0-client-info.properties resource — Stores the SDK name (springboot-api) and a version placeholder (${version}) that Gradle expands at build time via processResources.
• Updated JWTValidator — Replaced the default UrlJwkProvider(domain) constructor with a custom createJwkProvider() method that attaches the Auth0-Client and Accept headers to all JWKS endpoint requests.
• Unit tests — Validates the header value is well-formed Base64 JSON with expected keys, and verifies caching behavior.

How it works

1. At build time, Gradle's processResources replaces ${version} in auth0-client-info.properties with the project version (e.g., 1.0.0-beta.0).
2. At runtime, TelemetryProvider.getHeaderValue() reads the properties file from the classpath and constructs a JSON payload:

{"name":"springboot-api","version":"1.0.0-beta.0","java":"17.0.17"}

3. The JSON is Base64url-encoded (no padding) and sent as the Auth0-Client header on every JWKS request:

Auth0-Client: eyJuYW1lIjoic3ByaW5nYm9vdC1hcGkiLCJ2ZXJzaW9uIjoiMS4wLjAtYmV0YS4wIiwiamF2YSI6IjE3LjAuMTcifQ

4. JWTValidator.createJwkProvider() constructs the full JWKS URL (https://{domain}/.well-known/jwks.json) and passes custom headers to UrlJwkProvider.

Working sample

// JWTValidator automatically includes telemetry — no user action needed
AuthOptions options = new AuthOptions("your-tenant.auth0.com", "https://your-api-audience");
JWTValidator validator = new JWTValidator(options);

// When validateToken is called, the JWKS fetch includes:
//   GET https://your-tenant.auth0.com/.well-known/jwks.json
//   Headers:
//     Accept: application/json
//     Auth0-Client: eyJuYW1lIjoic3ByaW5nYm9vdC1hcGkiLCJ2ZXJzaW9uIjoiMS4wLjAtYmV0YS4wIiwiamF2YSI6IjE3LjAuMTcifQ
DecodedJWT jwt = validator.validateToken(accessToken, headers,
httpRequestInfo);

You can also inspect the telemetry value directly:

String headerValue = TelemetryProvider.getHeaderValue();
// Decode to verify:
String json = new String(Base64.getUrlDecoder().decode(headerValue), StandardCharsets.UTF_8);
//  {"name":"springboot-api","version":"1.0.0-beta.0","java":"17.0.17"}