Spring Security 7.1 JWT authentication on Spring Boot 4.1

Runnable companion for https://ankurm.com/spring-security-7-1-jwt-authentication-guide/

- login -> token issue -> OncePerRequestFilter -> SecurityContext, end to end
- HS256 and RS256 variants (RS256 publishes a real JWKS endpoint)
- the same API secured by the built-in oauth2ResourceServer().jwt(), for comparison
- 11 documentation chapters under docs/, interlinked with the code
- docs/output/ is real captured output, regenerated by scripts/run-all.sh
- 13 passing tests pinning the 401-vs-403 contract and the CSRF failure

Verified against Spring Boot 4.1.1, Spring Security 7.1.1, JDK 25.0.4.1.

src/main/java/com/ankurm/jwtauth/JwtAuthDemoApplication.java

@@ -0,0 +1,31 @@
+package com.ankurm.jwtauth;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Runnable companion for the ankurm.com article
+ * "Spring Security 7.1 JWT Authentication: The Complete Guide (Spring Boot 4.1)".
+ *
+ * <p>Two signing variants are wired as Spring profiles:
+ * <ul>
+ *   <li>{@code hs256} (default) - symmetric HMAC, one shared secret.</li>
+ *   <li>{@code rs256} - asymmetric RSA, private key signs, public key (JWKS) verifies.</li>
+ * </ul>
+ *
+ * <p>Two validation styles are wired as Spring profiles too:
+ * <ul>
+ *   <li>{@code manual} (default) - a hand-written {@code OncePerRequestFilter}.</li>
+ *   <li>{@code resourceserver} - Spring Security's built-in
+ *       {@code oauth2ResourceServer().jwt()} support.</li>
+ * </ul>
+ *
+ * @see docs/01-architecture.md
+ */
+@SpringBootApplication
+public class JwtAuthDemoApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(JwtAuthDemoApplication.class, args);
+    }
+}