feat: enhance text protocol conversion and advanced custom routing (#5825)

* refactor: consolidate relay protocol converters

* refactor relayconvert text converters

* feat: refine relay converters and advanced custom routing

* refactor: enhance logging and add thought signature handling for Gemini requests

* refactor: enhance channel cache and pricing endpoint handling for advanced custom models

* feat: preserve billing usage semantics

* feat: add protocol-aware billing usage

* Delete useless files

* chore: update action versions in workflow files

* chore: update Docker action versions in workflow files

* fix: harden billing usage settlement and hot-path route matching

- estimate Gemini completion tokens locally when billable usageMetadata is
  prompt-only but output content was received (e.g. client aborts the stream
  before the final chunk), and rebuild the attached billing_usage as estimated
  so settlement does not bill zero output tokens
- guard NewClaudeMessagesBillingUsage against all-zero ClaudeUsage, matching
  the OpenAI/Gemini constructors, so a zero billing_usage cannot override a
  non-zero top-level usage during settlement
- cache compiled advanced-custom route model regexes; they run on the request
  hot path and were recompiled per request
- move the effectiveBillingUsage remap to PostTextConsumeQuota only, and
  document that calculateTextQuotaSummary expects remapped usage
- document the updatePricingLock -> channelSyncLock lock ordering that
  InitChannelCache/CacheUpdateChannel rely on, and the aux-struct pitfall in
  GeminiChatResponse.UnmarshalJSON

relay/channel/ali/adaptor.go

@@ -75,10 +75,14 @@ func (a *Adaptor) ConvertClaudeRequest(c *gin.Context, info *relaycommon.RelayIn
 		return req, nil
 	}
 
-	oaiReq, err := service.ClaudeToOpenAIRequest(*req, info)
+	result, err := service.ConvertRequest(c, info, types.RelayFormatOpenAI, req)
 	if err != nil {
 		return nil, err
 	}
+	oaiReq, ok := result.Value.(*dto.GeneralOpenAIRequest)
+	if !ok {
+		return nil, fmt.Errorf("expected OpenAI chat completions request, got %T", result.Value)
+	}
 	if info.SupportStreamOptions && info.IsStream {
 		oaiReq.StreamOptions = &dto.StreamOptions{IncludeUsage: true}
 	}