fix(mempool): health-check 127.0.0.1 not localhost (stops false-unhealthy loop)

The archy-mempool-web health_check endpoint used http://localhost:8080.
Inside the frontend image, wget resolves `localhost` to ::1 (IPv6) first,
but nginx binds 0.0.0.0:8080 (IPv4) only -> the baked HealthCmd gets
"connection refused" every probe -> container is perpetually unhealthy ->
the reconciler recreates it forever (observed on .228: mempool container
re-Started every ~3 min, Health=unhealthy). Proven live: in-container
`wget http://localhost:8080/` = refused, `wget http://127.0.0.1:8080/` = OK.

Pin the probe to 127.0.0.1 so it matches nginx's IPv4 bind. Updated both
the source manifest and the embedded copy in releases/app-catalog.json
(the catalog overlay wins over the disk manifest on fleet nodes, so the
catalog copy is the one that actually reaches .228).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/archy-mempool-web/manifest.yml

@@ -33,7 +33,10 @@ app:
 
   health_check:
     type: http
-    endpoint: http://localhost:8080
+    # 127.0.0.1 not localhost: the image's wget resolves localhost to ::1 (IPv6)
+    # first, but nginx binds 0.0.0.0:8080 (IPv4) only -> localhost probe gets
+    # "connection refused" -> perpetual unhealthy -> health_monitor restart loop.
+    endpoint: http://127.0.0.1:8080
     path: /
     interval: 30s
     timeout: 5s

releases/app-catalog.json

@@ -235,7 +235,7 @@
           ],
           "health_check": {
             "type": "http",
-            "endpoint": "http://localhost:8080",
+            "endpoint": "http://127.0.0.1:8080",
             "path": "/",
             "interval": "30s",
             "timeout": "5s",