feat(backend): auto-stop/start daemon when switching backends

- Add local_providers with ollama and llamacpp configurations
- /backend command now stops current daemon before starting new one
- Start backends as detached processes to avoid blocking TUI
- Wait 500ms for daemon to initialize before switching

config/default.yaml

@@ -55,17 +55,19 @@ models:
   # fallback_chain. Useful for secondary API accounts or self-hosted
   # endpoints that aren't tied to a specific tier.
   #
-  # local_providers:
-  #   openrouter-backup:
-  #     provider: openrouter
-  #     model: anthropic/claude-sonnet-4
-  #   ollama-big:
-  #     provider: ollama
-  #     model: llama3.1:70b
-  #     endpoint: http://gpu-server:11434
+  # Use /backend <name> in the TUI to switch between these providers
+  local_providers:
+    ollama:
+      provider: ollama
+      model: glm-4.7-flash
+      endpoint: http://localhost:11434
+    llamacpp:
+      provider: llamacpp
+      model: gpt-oss-20b
+      endpoint: http://localhost:8080
   #
   # Then reference them in fallback_chain:
-  #   fallback_chain: [openrouter-backup, ollama-big, local]
+  #   fallback_chain: [ollama, llamacpp, local]
 
 hooks:
   confirm: