feat(pages): help-page (support) queue — stream, snapshot, respond, close

Phase 2 of docs/ADMIN_CONTROLS.md: surface the in-game help-page queue to the
website.

- BridgePages.cs: the queue has no EventSink, so it is polled (PageSweepSeconds,
  default 5s) and diffed, keyed by sender serial (one page per player) ->
  page.new / page.updated / page.closed. Inbound pages.snapshot -> pages.list;
  page.respond delivers a staff reply to the player (online: a gump now; offline:
  queued for next login; shows as "Staff") and can close; page.close removes it.
- BridgeConfig/Bridge.cfg: PageSweepSeconds. BridgeBoot: reload re-arms the poll,
  status reports it.
- sidecar/src/web.rs: GET /pages, POST /pages/{id}/respond, POST /pages/{id}/close.
- INTEGRATION.md: page events (§4) and endpoints (§6).
- tools/scaffolding/BridgePageProbe.cs: gated headless verification.

Verified live (probe-seeded tickets): snapshot returns the queue, the poll emits
page.new for both and page.closed on removal, respond -> 200, close removes the
page, unknown page -> 404.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0114TpmrNW4wNXsHq5CR72jQ

overlay/Scripts/Custom/Bridge/BridgeConfig.cs

@@ -17,6 +17,7 @@ namespace Server.Custom.Bridge
         public static int StatSweepSeconds { get; private set; }
         public static int DecaySweepSeconds { get; private set; }
         public static int EconomySweepSeconds { get; private set; }
+        public static int PageSweepSeconds { get; private set; }
 
         public static string LinkUrl { get; private set; }
 
@@ -50,6 +51,9 @@ namespace Server.Custom.Bridge
             StatSweepSeconds = Config.Get("Bridge.StatSweepSeconds", 30);
             DecaySweepSeconds = Config.Get("Bridge.DecaySweepSeconds", 60);
             EconomySweepSeconds = Config.Get("Bridge.EconomySweepSeconds", 300);
+            PageSweepSeconds = Config.Get("Bridge.PageSweepSeconds", 5);
+            if (PageSweepSeconds < 1)
+                PageSweepSeconds = 1;
 
             LinkUrl = Config.Get("Bridge.LinkUrl", "https://yoursite/link");