Port the observability platform to k3s and ship czy logs to it

k8s/ is now a faithful port of the mentor's Ansible Grafana stack
(Prometheus, Alertmanager, Loki, Tempo, Alloy, Grafana, node-exporter)
for the ledgerline-observability namespace on falken: same versions and
configs, one *.vione.cloud ingress per tool behind Traefik basic auth,
secrets generated by create-secrets.sh into gitignored files.

Two fixes over the Ansible role, both verified live: Tempo's
metrics-generator needs traces_storage or it runs no processors, and
Prometheus needs exemplar-storage to keep exemplars.

Ledgerline stays on czy; an Alloy agent in the Traefik override ships
its container logs to Loki. Roadmap and CLAUDE.md now point at k8s/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

k8s/tempo/tempo.yml

@@ -0,0 +1,47 @@
+server:
+  http_listen_port: 3200
+
+distributor:
+  receivers:
+    otlp:
+      protocols:
+        grpc:
+          endpoint: 0.0.0.0:4317
+        http:
+          endpoint: 0.0.0.0:4318
+
+ingester:
+  max_block_duration: 5m
+
+compactor:
+  compaction:
+    block_retention: 336h
+
+storage:
+  trace:
+    backend: local
+    wal:
+      path: /var/tempo/wal
+    local:
+      path: /var/tempo/blocks
+
+metrics_generator:
+  registry:
+    external_labels:
+      source: tempo
+  storage:
+    path: /var/tempo/generator/wal
+    remote_write:
+      - url: http://prometheus:9090/api/v1/write
+        send_exemplars: true
+  # Not in the Ansible template, which is broken without it: the
+  # local-blocks processor needs a traces WAL, and when it can't initialise,
+  # Tempo 2.8 starts *no* processors for the tenant ("local blocks processor
+  # requires traces wal"), so service-graphs and span-metrics never emit.
+  traces_storage:
+    path: /var/tempo/generator/traces
+
+overrides:
+  defaults:
+    metrics_generator:
+      processors: [service-graphs, span-metrics, local-blocks]