chore(alertmanager): untrack alertmanager.yml + ship .example template (post-SMTP migration)

Yesterday's deploy debug surfaced a SendGrid API key pasted into the
tracked monitoring/alertmanager/alertmanager.yml on prod, with the
in-repo file literally captioning the field "TODO: Paste your SG.xxx
API key here" — actively encouraging the anti-pattern. Forensic
follow-up (bash history lines 290-357) confirmed it was a user-driven
nano edit that was never committed, just left as a long-running local
mod. Three problems collapsed into this finding:

  1. Real SMTP credential lived in a tracked git file on prod.
  2. The SendGrid → mail1.myservices.hosting SMTP migration never
     touched alertmanager — it still pointed at smtp.sendgrid.net.
  3. The alertmanager container has been Up 13 days with the
     pre-paste empty smtp_auth_password loaded from disk, so prod's
     email alerting has been silently failing.

Resolution shipped here:

- `git rm --cached monitoring/alertmanager/alertmanager.yml` so the
  prod-edited file on each host stops being a tracked file and the
  credential can't accidentally reach git again.
- Add `monitoring/alertmanager/alertmanager.yml` to .gitignore.
- Ship `monitoring/alertmanager/alertmanager.yml.example` as the
  template — pre-filled with the post-migration non-secret routing
  (`mail1.myservices.hosting:587`, `support@wizard.lu` auth,
  `alerts@wizard.lu` From for inbox clarity), only `smtp_auth_password`
  left as `CHANGEME`. Includes inline guidance for the From-vs-auth
  rule that some SMTP relays enforce.

Per-host steps (Hetzner): backup the prod-edited file → revert local
change → pull → copy the template over the old file → fill in the
password → SIGHUP alertmanager. Doc reference will follow in the next
commit (Hetzner deploy doc still needs an "alertmanager.yml lives
outside git" footnote).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

monitoring/alertmanager/alertmanager.yml

@@ -1,58 +0,0 @@
-# Alertmanager Configuration for Orion Platform
-# Docs: https://prometheus.io/docs/alerting/latest/configuration/
-
-global:
-  resolve_timeout: 5m
-
-  # ─── SMTP Configuration (SendGrid) ──────────────────────────────────
-  # Sign up at sendgrid.com, create an API key, authenticate wizard.lu domain
-  # Username is literally the string "apikey", password is your SG.xxx API key
-  smtp_smarthost: 'smtp.sendgrid.net:587'       # SendGrid SMTP relay
-  smtp_from: 'alerts@wizard.lu'                 # Must match authenticated domain
-  smtp_auth_username: 'apikey'                  # Always "apikey" for SendGrid
-  smtp_auth_password: ''                        # TODO: Paste your SG.xxx API key here
-  smtp_require_tls: true
-
-route:
-  # Group alerts by name and severity
-  group_by: ['alertname', 'severity']
-  group_wait: 30s
-  group_interval: 5m
-  repeat_interval: 4h
-  receiver: 'email-warnings'
-
-  routes:
-    # Critical alerts: repeat every 1 hour
-    - match:
-        severity: critical
-      receiver: 'email-critical'
-      repeat_interval: 1h
-
-    # Warning alerts: repeat every 4 hours
-    - match:
-        severity: warning
-      receiver: 'email-warnings'
-      repeat_interval: 4h
-
-receivers:
-  - name: 'email-critical'
-    email_configs:
-      - to: 'admin@wizard.lu'                  # TODO: Replace with your alert recipient
-        send_resolved: true
-        headers:
-          Subject: '[CRITICAL] Orion: {{ .GroupLabels.alertname }}'
-
-  - name: 'email-warnings'
-    email_configs:
-      - to: 'admin@wizard.lu'                  # TODO: Replace with your alert recipient
-        send_resolved: true
-        headers:
-          Subject: '[WARNING] Orion: {{ .GroupLabels.alertname }}'
-
-# Inhibition rules — suppress warnings when critical is already firing
-inhibit_rules:
-  - source_match:
-      severity: 'critical'
-    target_match:
-      severity: 'warning'
-    equal: ['alertname', 'instance']

monitoring/alertmanager/alertmanager.yml.example

@@ -0,0 +1,71 @@
+# Alertmanager Configuration for Orion Platform — TEMPLATE
+# Docs: https://prometheus.io/docs/alerting/latest/configuration/
+#
+# This is the IN-REPO TEMPLATE. The real file on each host lives at
+# monitoring/alertmanager/alertmanager.yml (gitignored, never committed).
+# Copy this file to that path and fill in the CHANGEME values per
+# docs/deployment/hetzner-server-setup.md.
+
+global:
+  resolve_timeout: 5m
+
+  # ─── SMTP Configuration (mail1.myservices.hosting relay) ────────────
+  # Migrated from SendGrid to mail1.myservices.hosting on 2026-??-?? —
+  # same SMTP backend the app uses (see /admin/settings).
+  #
+  # smtp_from is set to alerts@wizard.lu for inbox routing clarity. Most
+  # SMTP relays allow the From: header to differ from the authenticated
+  # user, BUT some require them to match. If you see "550 sender not
+  # authorized" in the alertmanager logs after a reload, either:
+  #   1. Configure alerts@wizard.lu as a send-as alias on the support@
+  #      mailbox in your mail hosting control panel, or
+  #   2. Change smtp_from to 'support@wizard.lu' (less clear in inbox).
+  smtp_smarthost: 'mail1.myservices.hosting:587'
+  smtp_from: 'alerts@wizard.lu'
+  smtp_auth_username: 'support@wizard.lu'
+  smtp_auth_password: 'CHANGEME'                 # The /admin/settings SMTP password. NEVER commit a real value.
+  smtp_require_tls: true
+
+route:
+  # Group alerts by name and severity
+  group_by: ['alertname', 'severity']
+  group_wait: 30s
+  group_interval: 5m
+  repeat_interval: 4h
+  receiver: 'email-warnings'
+
+  routes:
+    # Critical alerts: repeat every 1 hour
+    - match:
+        severity: critical
+      receiver: 'email-critical'
+      repeat_interval: 1h
+
+    # Warning alerts: repeat every 4 hours
+    - match:
+        severity: warning
+      receiver: 'email-warnings'
+      repeat_interval: 4h
+
+receivers:
+  - name: 'email-critical'
+    email_configs:
+      - to: 'admin@wizard.lu'                    # Recipient mailbox for critical alerts
+        send_resolved: true
+        headers:
+          Subject: '[CRITICAL] Orion: {{ .GroupLabels.alertname }}'
+
+  - name: 'email-warnings'
+    email_configs:
+      - to: 'admin@wizard.lu'                    # Recipient mailbox for warning alerts
+        send_resolved: true
+        headers:
+          Subject: '[WARNING] Orion: {{ .GroupLabels.alertname }}'
+
+# Inhibition rules — suppress warnings when critical is already firing
+inhibit_rules:
+  - source_match:
+      severity: 'critical'
+    target_match:
+      severity: 'warning'
+    equal: ['alertname', 'instance']