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-common/src/main/java/org/botstandards/apix/common/AdminSandboxListResponse.java

@@ -0,0 +1,10 @@
+package org.botstandards.apix.common;
+
+import java.util.List;
+
+public record AdminSandboxListResponse(
+        long total,
+        int page,
+        int size,
+        List<AdminSandboxSummary> sandboxes
+) {}

apix-common/src/main/java/org/botstandards/apix/common/AdminSandboxSummary.java

@@ -0,0 +1,21 @@
+package org.botstandards.apix.common;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import java.time.Instant;
+
+/** Per-sandbox row in the admin list and stats endpoints. */
+public record AdminSandboxSummary(
+        String sandboxId,
+        String name,
+        String tier,
+        int ratePerMinute,
+        @JsonInclude(JsonInclude.Include.ALWAYS) Integer maxServices,
+        Instant createdAt,
+        Instant expiresAt,
+        boolean expired,
+        @JsonInclude(JsonInclude.Include.NON_NULL) String location,
+        @JsonInclude(JsonInclude.Include.NON_NULL) Double lat,
+        @JsonInclude(JsonInclude.Include.NON_NULL) Double lon,
+        long serviceCount,
+        long totalRequests
+) {}

apix-common/src/main/java/org/botstandards/apix/common/AdminStatsResponse.java

@@ -0,0 +1,17 @@
+package org.botstandards.apix.common;
+
+import java.util.List;
+import java.util.Map;
+
+public record AdminStatsResponse(
+        long totalSandboxes,
+        long activeSandboxes,
+        long expiredSandboxes,
+        Map<String, Long> byTier,
+        long totalServices,
+        long totalRequests,
+        /** Geo-points for the world map: one point per sandbox that provided a location. */
+        List<GeoPoint> registrarPoints
+) {
+    public record GeoPoint(double lat, double lon, String name, String tier) {}
+}