feat(observability): add SearXNG, Argos, and Pallas monitoring

- Add SearXNG syslog ingestion and blackbox health probes on miranda
  and rosalind for per-host attributable failure detection
- Scrape Argos MCP application metrics from miranda
- Add Pallas dashboard panels for downstream availability and turn
  error ratios

ansible/inventory/host_vars/miranda.incus.yml

@@ -10,21 +10,23 @@ services:
   - grafana_mcp
   - mcpo
   - neo4j_mcp
+  - searxng
 
 # Alloy
 alloy_log_level: "warn"
-argos_syslog_port: 51434
-neo4j_cypher_syslog_port: 51431
-grafana_mcp_syslog_port: 51433
-gitea_mcp_syslog_port: 51435
+argos_syslog_port: 51418
+neo4j_cypher_syslog_port: 51414
+grafana_mcp_syslog_port: 51413
+gitea_mcp_syslog_port: 51412
+searxng_syslog_port: 51419
 
 # Argos MCP Configuration
 argos_user: argos
 argos_group: argos
 argos_directory: /srv/argos
-argos_port: 25534
+argos_port: 20861
 argos_log_level: INFO
-argos_searxng_instances: http://rosalind.incus:22089/
+argos_searxng_instances: http://miranda.incus:22089/,http://rosalind.incus:22089/
 argos_cache_ttl: 300
 argos_max_results: 10
 argos_request_timeout: 30.0
@@ -48,7 +50,7 @@ neo4j_mcp_directory: /srv/neo4j_mcp
 grafana_mcp_user: grafana_mcp
 grafana_mcp_group: grafana_mcp
 grafana_mcp_directory: /srv/grafana_mcp
-grafana_mcp_port: 25533
+grafana_mcp_port: 22063
 grafana_mcp_grafana_host: prospero.incus
 grafana_mcp_grafana_port: 3000
 grafana_service_account_token: "{{ vault_grafana_service_account_token }}"
@@ -57,21 +59,28 @@ grafana_service_account_token: "{{ vault_grafana_service_account_token }}"
 gitea_mcp_user: gitea_mcp
 gitea_mcp_group: gitea_mcp
 gitea_mcp_directory: /srv/gitea_mcp
-gitea_mcp_port: 25535
+gitea_mcp_port: 22062
 gitea_mcp_host: https://gitea.ouranos.helu.ca
 gitea_mcp_access_token: "{{ vault_gitea_mcp_access_token }}"
 
 # Neo4j Cypher MCP
 neo4j_host: ariel.incus
-neo4j_bolt_port: 7687
-neo4j_auth_password: "{{ vault_neo4j_auth_password }}"
-neo4j_cypher_mcp_port: 25531
-
-# Nike MCP
-nike_mcp_url: http://puck.incus:25576/mcp
+neo4j_bolt_port: 22074
+neo4j_cypher_password: "{{ vault_neo4j_cypher_password }}"
+neo4j_cypher_mcp_port: 22064
+neo4j_mcp_server_allowed_hosts: localhost,127.0.0.1,miranda.incus
 
 # MCPO Config
 mcpo_user: mcpo
 mcpo_group: mcpo
 mcpo_directory: /srv/mcpo
 mcpo_port: 25530
+
+# SearXNG Configuration
+searxng_user: searxng
+searxng_group: searxng
+searxng_directory: /srv/searxng
+searxng_port: 22089
+searxng_base_url: http://miranda.incus:22089/
+searxng_instance_name: "Ouranos Search"
+searxng_secret_key: "{{ vault_searxng_secret_key }}"