docs: rewrite README with structured overview and quick start guide

Replaces the minimal project description with a comprehensive README
including a component overview table, quick start instructions, common
Ansible operations, and links to detailed documentation. Aligns with
Red Panda Approval™ standards.

ansible/pplg/alertmanager.yml.j2

@@ -0,0 +1,148 @@
+global:
+  resolve_timeout: 5m
+  smtp_smarthost: '{{ smtp_host }}:{{ smtp_port }}'
+  smtp_from: '{{ smtp_from }}'
+  smtp_require_tls: false
+
+route:
+  group_by: ['alertname', 'instance', 'severity']
+  group_wait: 30s
+  group_interval: 5m
+  repeat_interval: 4h
+  receiver: 'email'
+  routes:
+  - match:
+      severity: critical
+    receiver: 'email-critical'
+    continue: true
+  - match:
+      severity: warning
+    receiver: 'email-warning'
+    continue: true
+  - match:
+      severity: info
+    receiver: 'email-info'
+    repeat_interval: 24h
+
+inhibit_rules:
+  - source_match:
+      severity: 'critical'
+    target_match:
+      severity: 'warning'
+    equal: ['alertname', 'instance']
+
+receivers:
+- name: 'email-critical'
+  email_configs:
+  - to: 'hostmaster+critical@ouranos.helu.ca'
+    send_resolved: true
+    html: true
+    headers:
+      Subject: '🚨 [CRITICAL] {{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+    text: |-
+      {{ "{{" }} range .Alerts {{ "}}" }}
+      {{ "{{" }} .Annotations.description {{ "}}" }}
+
+      Instance: {{ "{{" }} .Labels.instance {{ "}}" }}
+      {{ "{{" }} end {{ "}}" }}
+
+- name: 'email-warning'
+  email_configs:
+  - to: 'hostmaster+warning@ouranos.helu.ca'
+    send_resolved: true
+    html: true
+    headers:
+      Subject: '⚠️ [WARNING] {{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+    text: |-
+      {{ "{{" }} range .Alerts {{ "}}" }}
+      {{ "{{" }} .Annotations.description {{ "}}" }}
+
+      Instance: {{ "{{" }} .Labels.instance {{ "}}" }}
+      {{ "{{" }} end {{ "}}" }}
+
+- name: 'email-info'
+  email_configs:
+  - to: 'hostmaster+info@ouranos.helu.ca'
+    send_resolved: false
+    html: true
+    headers:
+      Subject: '{{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+    text: '{{ "{{" }} range .Alerts {{ "}}" }}{{ "{{" }} .Annotations.description {{ "}}" }}{{ "{{" }} end {{ "}}" }}'
+
+- name: 'email'
+  email_configs:
+  - to: 'hostmaster+alerts@ouranos.helu.ca'
+    send_resolved: true
+    html: true
+    headers:
+      Subject: '[{{ "{{" }} .GroupLabels.severity | default "ALERT" {{ "}}" }}] {{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+    text: |-
+      {{ "{{" }} range .Alerts {{ "}}" }}
+      {{ "{{" }} .Annotations.description {{ "}}" }}
+
+      Instance: {{ "{{" }} .Labels.instance {{ "}}" }}
+      Severity: {{ "{{" }} .Labels.severity {{ "}}" }}
+      {{ "{{" }} end {{ "}}" }}
+
+# --- Pushover receivers (disabled for smtp4dev testing) ---
+# To re-enable: uncomment these receivers and update the route receiver names
+#   from email-*/email back to pushover-*/pushover
+#
+# - name: 'pushover-critical'
+#   pushover_configs:
+#   - user_key: '{{ pushover_user_key }}'
+#     token: '{{ pushover_api_token }}'
+#     send_resolved: true
+#     html: true
+#     priority: '2'
+#     retry: 30
+#     expire: 3600
+#     title: '🚨 [CRITICAL] {{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+#     message: |-
+#       {{ "{{" }} range .Alerts {{ "}}" }}
+#       {{ "{{" }} .Annotations.description {{ "}}" }}
+#       Instance: {{ "{{" }} .Labels.instance {{ "}}" }}
+#       {{ "{{" }} end {{ "}}" }}
+#
+# - name: 'pushover-warning'
+#   pushover_configs:
+#   - user_key: '{{ pushover_user_key }}'
+#     token: '{{ pushover_api_token }}'
+#     send_resolved: true
+#     html: true
+#     priority: '1'
+#     retry: 30
+#     expire: 3600
+#     title: '⚠️ [WARNING] {{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+#     message: |-
+#       {{ "{{" }} range .Alerts {{ "}}" }}
+#       {{ "{{" }} .Annotations.description {{ "}}" }}
+#       Instance: {{ "{{" }} .Labels.instance {{ "}}" }}
+#       {{ "{{" }} end {{ "}}" }}
+#
+# - name: 'pushover-info'
+#   pushover_configs:
+#   - user_key: '{{ pushover_user_key }}'
+#     token: '{{ pushover_api_token }}'
+#     send_resolved: false
+#     html: true
+#     priority: '0'
+#     title: '{{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+#     message: '{{ "{{" }} range .Alerts {{ "}}" }}{{ "{{" }} .Annotations.description {{ "}}" }}{{ "{{" }} end {{ "}}" }}'
+#
+# - name: 'pushover'
+#   pushover_configs:
+#   - user_key: '{{ pushover_user_key }}'
+#     token: '{{ pushover_api_token }}'
+#     send_resolved: true
+#     html: true
+#     priority: '1'
+#     retry: 30
+#     expire: 3600
+#     title: '[{{ "{{" }} .GroupLabels.severity | default "ALERT" {{ "}}" }}] {{ "{{" }} .GroupLabels.alertname {{ "}}" }}'
+#     message: |-
+#       {{ "{{" }} range .Alerts {{ "}}" }}
+#       {{ "{{" }} .Annotations.description {{ "}}" }}
+#       Instance: {{ "{{" }} .Labels.instance {{ "}}" }}
+#       Severity: {{ "{{" }} .Labels.severity {{ "}}" }}
+#       {{ "{{" }} end {{ "}}" }}