docs: improve local backend reliability and documentation

- Switch local endpoints from localhost to 127.0.0.1 to avoid IPv6 resolution issues\n- Add recommended Ollama user systemd service example with keep-alive and CUDA support

config/default.yaml

@@ -186,11 +186,11 @@ models:
     ollama:
       provider: ollama
       model: glm-4.7-flash
-      endpoint: http://localhost:11434
+      endpoint: http://127.0.0.1:11434
     llamacpp:
       provider: llamacpp
       model: gpt-oss-20b
-      endpoint: http://localhost:8080
+      endpoint: http://127.0.0.1:8080
   #
   # Then reference them in fallback_chain:
   #   fallback_chain: [ollama, llamacpp, local]
@@ -311,7 +311,7 @@ memory:
     enabled: true
     provider: ollama
     model: nomic-embed-text
-    endpoint: http://localhost:11434
+    endpoint: http://127.0.0.1:11434
     chunk_size: 512
     chunk_overlap: 50
     top_k: 5
@@ -565,7 +565,7 @@ automation:
 #   enabled: true
 #   provider:
 #     type: custom                            # openai, groq, ollama, llamacpp, custom
-#     endpoint: "http://localhost:18801/v1/audio/transcriptions"
+#     endpoint: "http://127.0.0.1:18801/v1/audio/transcriptions"
 #     api_key: "${WHISPER_API_KEY}"            # Optional Bearer token
 #     model: "whisper-1"                       # Model name (default: whisper-1)
 #   talk_mode: