feat: add LicenseInfo and Feature domain model

- Feature enum with topology, lineage, correlation, debugger, replay
- LicenseInfo record with tier, features, limits, issuedAt, expiresAt
- Open mode factory method for standalone/dev usage

cameleer3-server-core/src/main/java/com/cameleer3/server/core/license/Feature.java

@@ -0,0 +1,9 @@
+package com.cameleer3.server.core.license;
+
+public enum Feature {
+    topology,
+    lineage,
+    correlation,
+    debugger,
+    replay
+}

cameleer3-server-core/src/main/java/com/cameleer3/server/core/license/LicenseInfo.java

@@ -0,0 +1,30 @@
+package com.cameleer3.server.core.license;
+
+import java.time.Instant;
+import java.util.Map;
+import java.util.Set;
+
+public record LicenseInfo(
+        String tier,
+        Set<Feature> features,
+        Map<String, Integer> limits,
+        Instant issuedAt,
+        Instant expiresAt
+) {
+    public boolean isExpired() {
+        return expiresAt != null && Instant.now().isAfter(expiresAt);
+    }
+
+    public boolean hasFeature(Feature feature) {
+        return features.contains(feature);
+    }
+
+    public int getLimit(String key, int defaultValue) {
+        return limits.getOrDefault(key, defaultValue);
+    }
+
+    /** Open license — all features enabled, no limits. Used when no license is configured. */
+    public static LicenseInfo open() {
+        return new LicenseInfo("open", Set.of(Feature.values()), Map.of(), Instant.now(), null);
+    }
+}