perf(agent-core-v2): limit config env reads by domain

.changeset/quiet-config-reads.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Reduce CPU usage during agent turns.

packages/agent-core-v2/src/app/auth/configSection.ts

@@ -80,6 +80,7 @@ export const servicesEnvBindings: EnvBindings<ServicesConfig> = envBindings(
 );
 
 const servicesCredentialEnvOverlay: ConfigEffectiveOverlay = {
+  domains: [SERVICES_SECTION],
   apply(effective, getEnv, validate) {
     const services = effective[SERVICES_SECTION];
     if (!isPlainObject(services)) return [];

packages/agent-core-v2/src/app/config/config.ts

@@ -111,6 +111,7 @@ export interface RegisterSectionOptions<T> {
 }
 
 export interface ConfigEffectiveOverlay {
+  readonly domains?: readonly string[];
   apply(
     effective: Record<string, unknown>,
     getEnv: (name: string) => string | undefined,

packages/agent-core-v2/src/app/config/configService.ts

@@ -401,6 +401,15 @@ export class ConfigService extends Disposable implements IConfigService {
     if (Object.prototype.hasOwnProperty.call(this.memory, domain)) {
       return this.memory[domain] as T;
     }
+    if (
+      this.registry
+        .listEffectiveOverlays()
+        .every((overlay) => overlay.domains !== undefined && !overlay.domains.includes(domain))
+    ) {
+      const effective: ResolvedConfig = { [domain]: this.validated[domain] };
+      this.applySectionEnvBindings(effective, false, domain);
+      return effective[domain] as T;
+    }
     return this.freshEffective()[domain] as T;
   }
 
@@ -766,9 +775,14 @@ export class ConfigService extends Disposable implements IConfigService {
     return names;
   }
 
-  private applySectionEnvBindings(effective: ResolvedConfig, reportErrors: boolean): void {
+  private applySectionEnvBindings(
+    effective: ResolvedConfig,
+    reportErrors: boolean,
+    domain?: string,
+  ): void {
     const getEnv = (name: string): string | undefined => this.bootstrap.getEnv(name);
     for (const section of this.registry.listSections()) {
+      if (domain !== undefined && section.domain !== domain) continue;
       if (section.env === undefined) continue;
       const base = effective[section.domain];
       const envValues = this.sectionEnvNames(section).map(getEnv);

packages/agent-core-v2/src/app/kosongConfig/envOverlay.ts

@@ -85,6 +85,7 @@ function withoutKey(value: unknown, key: string): unknown {
 }
 
 export const kimiModelEnvOverlay: ConfigEffectiveOverlay = {
+  domains: ['models', 'providers', 'defaultModel', 'modelOverrides'],
   apply(effective, getEnv, validate) {
     const model = trimmed(getEnv('KIMI_MODEL_NAME'));
     const temperature = parseFloatEnv(