Improve WeChat MP replies and ship MindSpace/H5 production updates.

Add WeChat service account routing with sync acks, connectivity tests, and context isolation; document deploy runbooks; and bundle related MindSpace, voice, Plaza, and server gateway changes for production rollout.

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

billing.test.mjs

@@ -49,6 +49,30 @@ test('computeDeltaCostCents ignores backend USD cost unless explicitly enabled',
   });
   const rmbConfig = { ...config, useBackendCost: false };
   assert.equal(computeDeltaCostCents(previous, current, rmbConfig), 5);
-  const usdConfig = { ...config, useBackendCost: true };
+  // 成本模式默认 margin=1：deltaUsd 0.01 × 7.2 × 100 = 7.2 → ceil = 8
+  const usdConfig = { ...config, useBackendCost: true, marginMultiplier: 1 };
   assert.equal(computeDeltaCostCents(previous, current, usdConfig), 8);
 });
+
+test('computeDeltaCostCents applies margin multiplier in cost mode', () => {
+  const previous = { lastInputTokens: 0, lastOutputTokens: 0, lastAccumulatedCost: 0 };
+  const current = normalizeTokenState({
+    accumulatedInputTokens: 1_000_000,
+    accumulatedOutputTokens: 10_000,
+    accumulatedCost: 0.25,
+  });
+  // deltaUsd 0.25 × 7.2 × 100 × 3 = 540 分（而非 flat token 的 2060 分）
+  const costConfig = { ...config, useBackendCost: true, marginMultiplier: 3 };
+  assert.equal(computeDeltaCostCents(previous, current, costConfig), 540);
+});
+
+test('computeDeltaCostCents falls back to token path when accumulatedCost missing', () => {
+  const previous = { lastInputTokens: 0, lastOutputTokens: 0 };
+  const current = normalizeTokenState({
+    accumulatedInputTokens: 1000,
+    accumulatedOutputTokens: 500,
+    // 上游未回传 accumulatedCost → 即便开启成本模式也回退 token 计费
+  });
+  const costConfig = { ...config, useBackendCost: true, marginMultiplier: 3 };
+  assert.equal(computeDeltaCostCents(previous, current, costConfig), 5);
+});