fix: 尝试修复多轮对话缓存失效 skill 提升的问题

src/utils/attachments.ts

@@ -819,6 +819,10 @@ export async function getAttachments(
         !options?.skipSkillDiscovery
           ? [
               maybe('skill_discovery', async () => {
+                if (suppressNextDiscovery) {
+                  suppressNextDiscovery = false
+                  return []
+                }
                 const result = await skillSearchModules.prefetch.getTurnZeroSkillDiscovery(
                   input,
                   messages ?? [],
@@ -2638,6 +2642,7 @@ const sentSkillNames = new Map<string, Set<string>>()
 export function resetSentSkillNames(): void {
   sentSkillNames.clear()
   suppressNext = false
+  suppressNextDiscovery = false
 }
 
 /**
@@ -2661,6 +2666,18 @@ export function suppressNextSkillListing(): void {
 }
 let suppressNext = false
 
+/**
+ * Suppress the next skill-discovery injection on resume. Same rationale as
+ * suppressNextSkillListing: skill_discovery attachments are not persisted to
+ * transcript for non-ant users, so the prior process's discovery result is
+ * already in the conversation history the model sees. Re-generating it would
+ * inject duplicate content and bust the prompt cache prefix.
+ */
+export function suppressNextSkillDiscovery(): void {
+  suppressNextDiscovery = true
+}
+let suppressNextDiscovery = false
+
 // When skill-search is enabled and the filtered (bundled + MCP) listing exceeds
 // this count, fall back to bundled-only. Protects MCP-heavy users (100+ servers)
 // from truncation while keeping the turn-0 guarantee for typical setups.