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/mcpo/config.json.j2

@@ -4,47 +4,17 @@
       "command": "/srv/mcpo/.venv/bin/python",
       "args": ["/srv/mcpo/.venv/bin/mcp-server-time", "--local-timezone=America/Toronto"]
     },
-    "upstash-context7": {
-      "command": "npx",
-      "args": [
-        "-y",
-        "@upstash/context7-mcp"
-      ]
-    },
-    "angelia": {
-      "url": "https://ouranos.helu.ca/mcp/sse/",
-      "headers": {
-        "Authorization": "Bearer LmDTU1OoQm7nk8-T7NtGwwA5aut7LqcpVYpLxRKUS51klljJkFUbmu3KYnR8V6Ww"
-      }
-    },
     "argos": {
       "type": "streamable_http",
       "url": "{{argos_mcp_url}}"
     },
-    "athena": {
-      "url": "https://athena.ouranos.helu.ca/mcp/sse/",
-      "headers": {
-        "Authorization": "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIyIiwidXNlcl9pZCI6MiwidXNlcm5hbWUiOiJyQGhlbHUuY2EiLCJpc3MiOiJhdGhlbmEiLCJhdWQiOiJhdGhlbmEtbWNwIiwiaWF0IjoxNzczODc4MDgwLCJrZXlfbmFtZSI6Ik1pcmFuZGEgTUNQTyBLZXkiLCJ0ZW5hbnRfaWQiOjF9.bpFKRbfEygKOW6_UlfQ7H5ZZZ5-LgMJ2UP653GhpZ5A"
-    },
-    "caliban": {
-      "type": "streamable_http",
-      "url": "{{caliban_mcp_url}}"
-    },
     "gitea": {
       "type": "streamable_http",
       "url": "{{gitea_mcp_url}}"
     },
-    "korax": {
-      "type": "streamable_http",
-      "url": "{{korax_mcp_url}}"
-    },
     "neo4j-cypher": {
       "type": "streamable_http",
       "url": "{{neo4j_mcp_url}}"
-    },
-    "nike": {
-      "type": "streamable_http",
-      "url": "{{nike_mcp_url}}"
     }
   }
 }