feat(admin): apix-admin UI at admin.api-index.org

Internal maintainer dashboard: global stats, sandbox list with
tier-filter and pagination, sandbox drill-down with D3 world map,
tier-promotion form. API-key auth via HttpOnly cookie. Port 8084,
rolling a/b deploy alongside the existing service pairs.

- apix-common: AdminSandboxSummary, AdminSandboxListResponse, AdminStatsResponse DTOs
- apix-registry: AdminResource (4 endpoints), SandboxService.listAllSandboxes + getGlobalStats
- apix-registry: SandboxResource GET /{uuid}/dashboard endpoint (was missing — fixes portal 500)
- apix-portal: RegistryClient path corrected to /dashboard
- apix-admin: new Quarkus module — auth filter, registry REST client, 3 resources, 6 Qute templates, admin.js
- infra: Dockerfile.admin, docker-compose admin-a/b services, Caddyfile admin.api-index.org block
- scripts: deploy-bluegreen.sh extended for admin-a/b

Co-Authored-By: Mira Rehfeld <noreply@anthropic.com>

apix-admin/pom.xml

@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
+                             https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.botstandards</groupId>
+        <artifactId>apix-parent</artifactId>
+        <version>${revision}</version>
+    </parent>
+
+    <artifactId>apix-admin</artifactId>
+    <name>APIX :: Admin</name>
+    <description>Internal maintainer UI at admin.api-index.org. API-key auth, no username/password. Port 8084.</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.botstandards</groupId>
+            <artifactId>apix-common</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-rest</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-rest-qute</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-rest-client</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-rest-client-jackson</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-smallrye-health</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>${quarkus.platform.group-id}</groupId>
+                <artifactId>quarkus-maven-plugin</artifactId>
+                <extensions>true</extensions>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>build</goal>
+                            <goal>generate-code</goal>
+                            <goal>generate-code-tests</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>