chore(ai): Remove LobeChat and simplify Ollama URL

Removed the `lobechat` group and its associated configuration from `stacks/ai/ai-frontend.nomad` as this application is no longer required.

Updated the `OLLAMA_BASE_URL` for the `ai-frontend` (OpenWebUI) task to use the concise `ollama` service name (`http://ollama:11434`). This leverages Nomad's built-in service discovery more efficiently, simplifying the URL from `http://ollama.service.consul:11434`.

Additionally, the `memory` allocation for the `ai-frontend` task was increased from `1024` to `4000` to provide more stable resources for the OpenWebUI application.

stacks/ai/ai-frontend.nomad

@@ -42,7 +42,7 @@ job "ai-frontend" {
       driver = "podman"
 
       env {
-        OLLAMA_BASE_URL = "http://ollama.service.consul:11434"
+        OLLAMA_BASE_URL = "http://ollama:11434"
       }
 
       config {
@@ -51,68 +51,11 @@ job "ai-frontend" {
         volumes = [
           "/mnt/local-ssd/nomad/stacks/ai/ai-frontend/openwebui:/app/backend/data"
         ]
-        # Removed invalid dns_servers/dns_search from here
       }
 
       resources {
         cpu    = 1000
-        memory = 1024
-      }
-    }
-  }
-
-  # --- LobeChat ---
-  group "lobechat" {
-    count = 1
-
-    constraint {
-      attribute = "${attr.unique.hostname}"
-      value     = "hp1-home"
-    }
-
-    network {
-      port "http" {
-        static = 3210
-        to     = 3210
-      }
-
-      # ✅ DNS Moved Here
-      dns {
-        servers  = ["192.168.1.133"]
-        searches = ["service.consul"]
-      }
-    }
-
-    service {
-      name = "lobechat"
-      port = "http"
-      tags = ["traefik.enable=true"]
-
-      check {
-        type     = "http"
-        path     = "/"
-        interval = "20s"
-        timeout  = "2s"
-      }
-    }
-
-    task "server" {
-      driver = "podman"
-
-      env {
-        OLLAMA_PROXY_URL = "http://ollama.service.consul:11434"
-        ACCESS_CODE      = "securepassword123"
-      }
-
-      config {
-        image = "docker.io/lobehub/lobe-chat:v1.143.0"
-        ports = ["http"]
-        # Removed invalid dns_servers/dns_search from here
-      }
-
-      resources {
-        cpu    = 500
-        memory = 1024
+        memory = 4000
       }
     }
   }