hindsight: raise nginx ingress proxy read/send timeout to 300s (fixes reflect 504)

Scoped to the hindsight ingress (cosmic-rewind.local.mk-labs.cloud) only.
A slow agentic reflect (~132s on solar-pro4) exceeded the 60s default
proxy-read-timeout, causing nginx to return 504 before the app delivered 200.
Raising read+send to 300s lets the response land. No global configmap change.

Refs t_e3375410.

cluster/applications/hindsight/values.yaml

@@ -71,6 +71,10 @@ ingress:
   className: "nginx"
   annotations:
     cert-manager.io/cluster-issuer: "letsencrypt-prod"
+    # Raised read/send timeout so a slow agentic reflect (~132s on solar-pro4)
+    # can complete before nginx cuts the connection (was 60s default -> 504).
+    nginx.ingress.kubernetes.io/proxy-read-timeout: "300"
+    nginx.ingress.kubernetes.io/proxy-send-timeout: "300"
   hosts:
     - host: cosmic-rewind.local.mk-labs.cloud
       paths: