Deploy: change default HTTP port 8080 -> 8760

8080 is a very common, collision-prone port. 8760 (hours in a year) is an uncommon default that also avoids Home Assistant's 8123. Applied across Dockerfile (ASPNETCORE_URLS/EXPOSE), compose (mapping + healthcheck), the Unraid template, README and a code comment. The METERVAULT_PORT host override still works.

Claude-Session: https://claude.ai/code/session_01Kib2MniVFbD95fkgLgBBnB

src/App/Program.cs

@@ -60,7 +60,7 @@ try
     app.UseStatusCodePagesWithReExecute("/not-found", createScopeForStatusCodePages: true);
     app.UseSerilogRequestLogging();
     app.UseReverseProxyTrust();
-    // No HTTPS redirection: the app serves plain HTTP (port 8080) behind a reverse proxy
+    // No HTTPS redirection: the app serves plain HTTP (port 8760) behind a reverse proxy
     // that terminates TLS (SDD §10). HTTPS redirection here would break the container and proxy.
     app.UseAntiforgery();