refactor(license): extract cameleer-license-api module from server-core

Splits the pure license contract types (LicenseInfo, LicenseValidator,
LicenseState, LicenseStateMachine, LicenseLimits, DefaultTierLimits) into a
new cameleer-license-api module under package com.cameleer.license.

Why: cameleer-license-minter previously depended on cameleer-server-core for
these types, dragging cameleer-server-core + cameleer-common onto the
classpath of every minter consumer (notably cameleer-saas). The SaaS
management plane has no business carrying server-runtime types — it only
needs the license contract to mint and verify tokens.

After:
  cameleer-license-minter -> cameleer-license-api  (no server internals)
  cameleer-server-core    -> cameleer-license-api
  cameleer-saas           -> cameleer-license-minter -> cameleer-license-api

Verified: mvn -pl cameleer-license-minter dependency:tree shows the minter
no longer pulls cameleer-server-core or cameleer-common. Full reactor
verify (-DskipITs) green: 371 tests pass.

LicenseGate stays in server-core (server-runtime state holder, not contract).

Closes cameleer/cameleer-server#156

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cameleer-license-minter/src/main/java/com/cameleer/license/minter/LicenseMinter.java

@@ -1,6 +1,6 @@
 package com.cameleer.license.minter;
 
-import com.cameleer.server.core.license.LicenseInfo;
+import com.cameleer.license.LicenseInfo;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.node.ObjectNode;

cameleer-license-minter/src/main/java/com/cameleer/license/minter/cli/LicenseMinterCli.java

@@ -1,7 +1,7 @@
 package com.cameleer.license.minter.cli;
 
 import com.cameleer.license.minter.LicenseMinter;
-import com.cameleer.server.core.license.LicenseInfo;
+import com.cameleer.license.LicenseInfo;
 
 import java.io.PrintStream;
 import java.nio.file.Files;
@@ -107,7 +107,7 @@ public final class LicenseMinterCli {
                 }
                 try {
                     String pubB64 = Files.readString(Path.of(pubPath)).trim();
-                    new com.cameleer.server.core.license.LicenseValidator(pubB64, tenant).validate(token);
+                    new com.cameleer.license.LicenseValidator(pubB64, tenant).validate(token);
                     out.println("verified ok");
                 } catch (Exception ve) {
                     err.println("VERIFY FAILED: " + ve.getMessage());

cameleer-license-minter/src/test/java/com/cameleer/license/minter/LicenseMinterTest.java

@@ -1,7 +1,7 @@
 package com.cameleer.license.minter;
 
-import com.cameleer.server.core.license.LicenseInfo;
-import com.cameleer.server.core.license.LicenseValidator;
+import com.cameleer.license.LicenseInfo;
+import com.cameleer.license.LicenseValidator;
 import org.junit.jupiter.api.Test;
 
 import java.security.KeyPair;

cameleer-license-minter/src/test/java/com/cameleer/license/minter/cli/LicenseMinterCliTest.java

@@ -1,6 +1,6 @@
 package com.cameleer.license.minter.cli;
 
-import com.cameleer.server.core.license.LicenseValidator;
+import com.cameleer.license.LicenseValidator;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;