feat: add audit domain model, repository interface, AuditService, and unit test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-core/src/main/java/com/cameleer3/server/core/admin/AuditCategory.java

@@ -0,0 +1,5 @@
+package com.cameleer3.server.core.admin;
+
+public enum AuditCategory {
+    INFRA, AUTH, USER_MGMT, CONFIG
+}

cameleer3-server-core/src/main/java/com/cameleer3/server/core/admin/AuditRecord.java

@@ -0,0 +1,24 @@
+package com.cameleer3.server.core.admin;
+
+import java.time.Instant;
+import java.util.Map;
+
+public record AuditRecord(
+        long id,
+        Instant timestamp,
+        String username,
+        String action,
+        AuditCategory category,
+        String target,
+        Map<String, Object> detail,
+        AuditResult result,
+        String ipAddress,
+        String userAgent
+) {
+    /** Factory for creating new records (id and timestamp assigned by DB) */
+    public static AuditRecord create(String username, String action, AuditCategory category,
+                                      String target, Map<String, Object> detail, AuditResult result,
+                                      String ipAddress, String userAgent) {
+        return new AuditRecord(0, null, username, action, category, target, detail, result, ipAddress, userAgent);
+    }
+}

cameleer3-server-core/src/main/java/com/cameleer3/server/core/admin/AuditRepository.java

@@ -0,0 +1,25 @@
+package com.cameleer3.server.core.admin;
+
+import java.time.Instant;
+import java.util.List;
+
+public interface AuditRepository {
+
+    void insert(AuditRecord record);
+
+    record AuditQuery(
+            String username,
+            AuditCategory category,
+            String search,
+            Instant from,
+            Instant to,
+            String sort,
+            String order,
+            int page,
+            int size
+    ) {}
+
+    record AuditPage(List<AuditRecord> items, long totalCount) {}
+
+    AuditPage find(AuditQuery query);
+}

cameleer3-server-core/src/main/java/com/cameleer3/server/core/admin/AuditResult.java

@@ -0,0 +1,5 @@
+package com.cameleer3.server.core.admin;
+
+public enum AuditResult {
+    SUCCESS, FAILURE
+}

cameleer3-server-core/src/main/java/com/cameleer3/server/core/admin/AuditService.java

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+package com.cameleer3.server.core.admin;
+
+import jakarta.servlet.http.HttpServletRequest;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+
+import java.util.Map;
+
+public class AuditService {
+    private static final Logger log = LoggerFactory.getLogger(AuditService.class);
+    private final AuditRepository repository;
+
+    public AuditService(AuditRepository repository) {
+        this.repository = repository;
+    }
+
+    /** Log an action using the current SecurityContext for username */
+    public void log(String action, AuditCategory category, String target,
+                    Map<String, Object> detail, AuditResult result,
+                    HttpServletRequest request) {
+        String username = extractUsername();
+        log(username, action, category, target, detail, result, request);
+    }
+
+    /** Log an action with explicit username (for pre-auth contexts like login) */
+    public void log(String username, String action, AuditCategory category, String target,
+                    Map<String, Object> detail, AuditResult result,
+                    HttpServletRequest request) {
+        String ip = request != null ? request.getRemoteAddr() : null;
+        String userAgent = request != null ? request.getHeader("User-Agent") : null;
+        AuditRecord record = AuditRecord.create(username, action, category, target, detail, result, ip, userAgent);
+
+        repository.insert(record);
+
+        log.info("AUDIT: user={} action={} category={} target={} result={}",
+                username, action, category, target, result);
+    }
+
+    private String extractUsername() {
+        Authentication auth = SecurityContextHolder.getContext().getAuthentication();
+        if (auth != null && auth.getName() != null) {
+            String name = auth.getName();
+            return name.startsWith("user:") ? name.substring(5) : name;
+        }
+        return "unknown";
+    }
+}