Eliminate legacy gateway container (consolidate into router-gateway)

The gateway service was a redundant deployment of the same
StellaOps.Gateway.WebService binary already running as router-gateway.
It served no unique purpose — all traffic is handled by router-gateway
(slot 0). This removes the container, its route table entries, nginx
proxy blocks, health/quota stubs, and redirects STELLAOPS_GATEWAY_URL
to router.stella-ops.local so the Angular frontend resolves API base
URLs through the canonical frontdoor.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Platform/StellaOps.Platform.WebService/Properties/launchSettings.json

@@ -12,7 +12,7 @@
         "STELLAOPS_PLATFORM_URL": "https://platform.stella-ops.local",
         "STELLAOPS_ROUTER_URL": "https://router.stella-ops.local",
         "STELLAOPS_AUTHORITY_URL": "https://authority.stella-ops.local",
-        "STELLAOPS_GATEWAY_URL": "https://gateway.stella-ops.local",
+        "STELLAOPS_GATEWAY_URL": "https://router.stella-ops.local",
         "STELLAOPS_ATTESTOR_URL": "https://attestor.stella-ops.local",
         "STELLAOPS_EVIDENCELOCKER_URL": "https://evidencelocker.stella-ops.local",
         "STELLAOPS_SCANNER_URL": "https://scanner.stella-ops.local",

src/Platform/StellaOps.Platform.WebService/Services/PlatformHealthService.cs

@@ -16,7 +16,6 @@ public sealed class PlatformHealthService
     private static readonly string[] ServiceNames =
     {
         "authority",
-        "gateway",
         "orchestrator",
         "policy",
         "scanner",

src/Platform/StellaOps.Platform.WebService/Services/PlatformQuotaService.cs

@@ -16,7 +16,6 @@ public sealed class PlatformQuotaService
 {
     private static readonly PlatformQuotaDefinition[] Quotas =
     {
-        new("gateway.requests", "tenant", "requests", 100000m, 23000m, "month", "gateway"),
         new("orchestrator.jobs", "tenant", "jobs", 1000m, 120m, "day", "orchestrator"),
         new("storage.evidence", "tenant", "gb", 5000m, 2400m, "month", "storage")
     };