feat(cliproxy): implement model aliasing and hashing for Codex configurations, enhance request routing logic, and normalize Codex model entries

internal/watcher/synthesizer/config.go

@@ -147,6 +147,9 @@ func (s *ConfigSynthesizer) synthesizeCodexKeys(ctx *SynthesisContext) []*coreau
 		if ck.BaseURL != "" {
 			attrs["base_url"] = ck.BaseURL
 		}
+		if hash := diff.ComputeCodexModelsHash(ck.Models); hash != "" {
+			attrs["models_hash"] = hash
+		}
 		addConfigHeadersToAttrs(ck.Headers, attrs)
 		proxyURL := strings.TrimSpace(ck.ProxyURL)
 		a := &coreauth.Auth{