refactor(core): restructure conversation/channel/message domains and modernize deployment

- Replace chat package with conversation flow architecture
- Add channel identity avatar support (migration 0002)
- Refactor channel adapters, identities, and message routing
- Update frontend: simplify composables, modernize UI components
- Improve Docker builds with cache mounts and version metadata
- Optimize healthchecks and simplify service dependencies

internal/providers/service.go

@@ -232,7 +232,9 @@ func (s *Service) toGetResponse(provider sqlc.LlmProvider) GetResponse {
 // isValidClientType checks if a client type is valid
 func isValidClientType(clientType ClientType) bool {
 	switch clientType {
-	case ClientTypeOpenAI, ClientTypeOpenAICompat, ClientTypeAnthropic, ClientTypeGoogle, ClientTypeOllama:
+	case ClientTypeOpenAI, ClientTypeOpenAICompat, ClientTypeAnthropic, ClientTypeGoogle,
+		ClientTypeAzure, ClientTypeBedrock, ClientTypeMistral, ClientTypeXAI,
+		ClientTypeOllama, ClientTypeDashscope:
 		return true
 	default:
 		return false

internal/providers/types.go

@@ -10,7 +10,12 @@ const (
 	ClientTypeOpenAICompat ClientType = "openai-compat"
 	ClientTypeAnthropic    ClientType = "anthropic"
 	ClientTypeGoogle       ClientType = "google"
+	ClientTypeAzure        ClientType = "azure"
+	ClientTypeBedrock      ClientType = "bedrock"
+	ClientTypeMistral      ClientType = "mistral"
+	ClientTypeXAI          ClientType = "xai"
 	ClientTypeOllama       ClientType = "ollama"
+	ClientTypeDashscope    ClientType = "dashscope"
 )
 
 // CreateRequest represents a request to create a new LLM provider