chore: import upstream snapshot with attribution

tests/unit/compression/language-detect-select.test.ts

@@ -0,0 +1,50 @@
+/**
+ * Guards for B-LANG-DETECTOR + B-LANG-DORMANT.
+ *
+ * B-LANG-DETECTOR: the detector was first-match-wins on a single keyword, and some hint
+ * words are English-ambiguous ("configuration" in fr, "error" in es) → English text
+ * misclassified as fr/es. Now it is score-based and needs ≥2 hits to leave English.
+ *
+ * B-LANG-DORMANT: with autoDetectLanguage on but enabledPacks ["en"], detected non-English
+ * text fell back to the English pack, whose `articles` rule deletes foreign articles
+ * (pt-BR "a"/"o"). Auto-detect must use the detected pack (it always has rules).
+ */
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { detectCompressionLanguage } from "@omniroute/open-sse/services/compression/languageDetector.ts";
+import { cavemanCompress } from "@omniroute/open-sse/services/compression/caveman.ts";
+
+test("detector ignores single English-ambiguous keywords (configuration/error)", () => {
+  assert.equal(
+    detectCompressionLanguage("Please update the configuration and fix the error in the file"),
+    "en"
+  );
+});
+
+test("detector still recognizes genuine non-English text (>=2 native keywords)", () => {
+  assert.equal(detectCompressionLanguage("Por favor preciso do arquivo com erro"), "pt-BR");
+  assert.equal(detectCompressionLanguage("これはテストですコードを確認"), "ja");
+});
+
+test("auto-detect uses the detected pt-BR pack, not the mangling English pack (B-LANG-DORMANT)", () => {
+  // pt-BR prose with an article the English `articles` rule would delete ("a configuração").
+  const text =
+    "Por favor, você poderia revisar a configuração do arquivo? Obrigado pela ajuda com isso.";
+  const res = cavemanCompress({ messages: [{ role: "user", content: text }] } as Record<
+    string,
+    unknown
+  >, {
+    enabled: true,
+    autoDetectLanguage: true,
+    enabledLanguagePacks: ["en"], // the production-default that used to force the English pack
+    intensity: "full",
+    compressRoles: ["user"],
+    minMessageLength: 0,
+  } as Record<string, unknown>);
+  const rules = res.stats?.rulesApplied ?? [];
+  // A pt-BR rule must have run (proves the pt-BR pack was selected, not English).
+  assert.ok(
+    rules.some((r) => r.startsWith("pt_")),
+    `expected a pt_* rule to apply, got: ${JSON.stringify(rules)}`
+  );
+});