fix(bridge): 商品搜索结果按库存优先排序

bridge/src/prompts.js

@@ -21,6 +21,7 @@ TOOL DISCIPLINE:
 - search_email_history: only for a verified customer asking about their own past emails (quotes, previous inquiries, "I emailed you before"). Never use another person's email; the tool is scoped to the verified identity.
 - handoff_to_human: call when the customer explicitly asks for a human, is angry/complaining, or the request cannot be resolved with the available tools. Use it instead of only saying "I'll transfer you".
 - create_opportunity: as soon as company + a contact (name, email or phone) + product need are known, call it — email verification is NOT required for lead creation. Call it exactly once per customer. If it returns created=false, do not create another. If it returns crm_unavailable, tell the customer the team will follow up and do not retry immediately. NEVER use the words CRM or opportunity in a customer reply (say 'your request' / 'your inquiry' instead), never mention opportunity IDs, internal records, assigned users, or tool results, and never quote an opportunity name/reference. Only claim the request was recorded/registered if the tool actually returned created=true or an existing opportunity; never promise it without calling the tool.
+- CITATIONS / dropshipping: when the customer asks about dropshipping (dropshipping registration, orders, payment, shipment or returns), prefer the https://dropshipping.yehwang.com/faq/* URLs that appear in the search_kb source_urls. Do NOT replace them with similar www.yehwang.com pages; only fall back to www.yehwang.com when no dropshipping source is available. Cite the URL that actually supports the answer.
 
 VERIFICATION (important):
 - Order lookup requires a verified customer. Opportunity creation does NOT require verification (company + contact + need is enough).

bridge/src/tools.js

@@ -421,7 +421,8 @@ function createTools(cfg, deps = {}) {
       const cmd = {
         keyword: rpcQuery,
         page: 1,
-        pageSize: limit,
+        // 多取候选，下面按库存排序后再截断到 limit，避免缺货商品占满前几条
+        pageSize: limit * 4,
         languageId: profile.languageId,
         tenantId: profile.tenantId,
         currencyCode: profile.currencyCode || '',
@@ -439,7 +440,6 @@ function createTools(cfg, deps = {}) {
       const list = Array.isArray(paging) ? paging : (paging.data || paging.list || []);
       total = result.total != null ? result.total : (paging.total != null ? paging.total : null);
       items = (Array.isArray(list) ? list : [])
-        .slice(0, limit)
         .map((p) => {
           const name = p.spuName || p.name || p.title || null;
           const sku = p.sku || p.model || (Array.isArray(p.skus) && p.skus[0] ? p.skus[0].productId : null);
@@ -458,7 +458,13 @@ function createTools(cfg, deps = {}) {
             mark_price: p.markPriceWithCurrency || null,
           };
         })
-        .filter((p) => p.name);
+        .filter((p) => p.name)
+        // 有库存优先：stock>0 → 0，未知 → 1，缺货 → 2；sort 稳定，保留 RPC 原顺序
+        .sort((a, b) => {
+          const rank = (p) => (p.stock > 0 ? 0 : p.stock === null ? 1 : 2);
+          return rank(a) - rank(b);
+        })
+        .slice(0, limit);
     } catch (err) {
       catalogError = err.message;
     }

bridge/test/prompts.test.js

@@ -0,0 +1,12 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const { SYSTEM_PROMPT, buildSystemPrompt } = require('../src/prompts');
+
+test('prompt: dropshipping answers prefer dropshipping source urls', () => {
+  assert.match(SYSTEM_PROMPT, /dropshipping\.yehwang\.com\/faq\//);
+  assert.match(SYSTEM_PROMPT, /Do NOT replace them with similar www\.yehwang\.com pages/i);
+  const built = buildSystemPrompt({ verified: false, site: 'www', channel: 'livechat' });
+  assert.match(built, /dropshipping\.yehwang\.com\/faq\//);
+});