ingress latency: add histogram buckets, fix restarts, right-size memory

- Traefik: add fine-grained Prometheus histogram buckets (0.01-30s) for meaningful P50/P99
- Calibre: relax liveness probe (timeout 5→10s, threshold 3→6) to stop NFS-caused restarts
- Novelapp: increase memory 128Mi/256Mi → 640Mi/640Mi (confirmed OOMKilled, VPA upper 505Mi)
- Forgejo: increase memory 256Mi → 384Mi (at 80% of limit, VPA upper 311Mi)
- ActualBudget: add explicit resources to prevent silent LimitRange defaults
- Docs: update Nextcloud note from 4Gi → 8Gi limit (Apache spike history)

stacks/calibre/main.tf

@@ -244,9 +244,9 @@ resource "kubernetes_deployment" "calibre-web-automated" {
               path = "/"
               port = 8083
             }
-            timeout_seconds   = 5
+            timeout_seconds   = 10
             period_seconds    = 30
-            failure_threshold = 3
+            failure_threshold = 6
           }
           resources {
             requests = {