feat(router): improve direct_chat fast-path and add 103 token env sync

Route explicit text-only Q&A away from Agent before page-generation rules,
and add a script to enable Router + tighter memory budgets on 103 without
changing the global deepseek-v4-pro model.

Co-authored-by: Cursor <cursoragent@cursor.com>

chat-intent-router.mjs

@@ -15,11 +15,11 @@ import {
   resolveMemoryInterventionMode,
 } from './memory-intervention.mjs';
 import { filterMemoriesByQuery } from './memory-legacy-fallback.mjs';
-import { matchDirectChatFaqRule } from './chat-intent-router-rules.mjs';
+import { matchDirectChatFaqRule, isExplicitTextOnlyRequest } from './chat-intent-router-rules.mjs';
 import { isGoalRunIntent } from './goal-run-intent.mjs';
 import { pgvectorMemoryBackendInternals } from './memory-v2-pgvector.mjs';
 
-export { matchDirectChatFaqRule, DIRECT_CHAT_FAQ_RULES, FAQ_EXCLUSION_PATTERNS } from './chat-intent-router-rules.mjs';
+export { matchDirectChatFaqRule, DIRECT_CHAT_FAQ_RULES, FAQ_EXCLUSION_PATTERNS, isExplicitTextOnlyRequest } from './chat-intent-router-rules.mjs';
 
 export const CHAT_INTENT_ROUTE = {
   DIRECT_CHAT: 'direct_chat',
@@ -1083,6 +1083,14 @@ export function classifyWithRules({
       reason: '用户在询问个人记忆或历史对话',
     }, { source: 'rule' }), decisionContext);
   }
+  if (includeIntentPatterns && normalized && isExplicitTextOnlyRequest(normalized)) {
+    const faqMatch = matchDirectChatFaqRule(normalized);
+    return finalizeRouterClassification(normalizeClassification({
+      route: CHAT_INTENT_ROUTE.DIRECT_CHAT,
+      confidence: 0.96,
+      reason: faqMatch?.reason ?? '用户明确要求纯文字、不生成页面',
+    }, { source: 'rule' }), decisionContext);
+  }
   if (hasPriorAgentConversation(sessionId, sessionMessageCount)) {
     const reason = isAgentSessionContinueText(normalized)
       ? 'Agent 会话确认/续聊'
@@ -1093,6 +1101,16 @@ export function classifyWithRules({
       reason,
     }, { source: 'rule' }), decisionContext);
   }
+  if (includeIntentPatterns && normalized) {
+    const faqMatch = matchDirectChatFaqRule(normalized);
+    if (faqMatch) {
+      return finalizeRouterClassification(normalizeClassification({
+        route: CHAT_INTENT_ROUTE.DIRECT_CHAT,
+        confidence: 0.94,
+        reason: faqMatch.reason,
+      }, { source: 'rule' }), decisionContext);
+    }
+  }
   if (includeIntentPatterns && normalized && isPageDataDevIntent(normalized)) {
     return finalizeRouterClassification(normalizeClassification({
       route: CHAT_INTENT_ROUTE.AGENT,
@@ -1142,16 +1160,6 @@ export function classifyWithRules({
   if (includeIntentPatterns && normalized && isRealtimeInfoQuestion(normalized)) {
     return finalizeRouterClassification(buildRealtimeInfoClassification(), decisionContext);
   }
-  if (includeIntentPatterns && normalized) {
-    const faqMatch = matchDirectChatFaqRule(normalized);
-    if (faqMatch) {
-      return finalizeRouterClassification(normalizeClassification({
-        route: CHAT_INTENT_ROUTE.DIRECT_CHAT,
-        confidence: 0.94,
-        reason: faqMatch.reason,
-      }, { source: 'rule' }), decisionContext);
-    }
-  }
   if (
     includeIntentPatterns &&
     normalized &&