audit-4: classifier understands Spanish negations (veto unchanged)

Merchants write in Spanish; negations like nunca, lamentablemente or
no podemos must veto approval exactly like their English counterparts.
Previously an all-Spanish rejection mail could fall through to OTHER,
and a mixed mail with the approval word in English approved despite a
Spanish negation.

- negation list adds: nunca, jamas, tampoco, ningun/ninguna, nadie,
  nada, no podemos, no es posible, no aceptamos, rechaz*, descartad*,
  lamentablemente, no ha sido aprobad*, no procede
- new Spanish REJECTION rule (rechaz*, solicitud denegada, no cumple
  los requisitos) and Spanish APPROVAL rule (aprob*, aceptad*,
  bienvenid*, encantados de trabajar)
- veto rule unchanged: any negation anywhere -> needs_review
- tests: 15 new (12 veto cases incl. 2 mixed-language, pure-Spanish
  approval still approves, Spanish rejection classifies rejection)

Gate: ruff 0 · 96 unit + 1 PG integration · gitleaks clean.

cayceops/components/maild/classify.py

@@ -19,10 +19,17 @@ from cayceops.models import MailClassification
 
 _APPROVAL_WORDS = re.compile(r"\b(approv|accept|welcome)", re.I)
 
-# any of these tokens anywhere in the mail vetoes an `approval` result
+# any of these tokens anywhere in the mail vetoes an `approval` result.
+# English and Spanish (merchants write in both; mixed mails are common).
 _NEGATIONS = re.compile(
     r"\b(not|no|never|cannot|can'?t|won'?t|hasn'?t|isn'?t|"
-    r"no\s+longer|unable|decline\w*|regret\w*|unfortunately)\b",
+    r"no\s+longer|unable|decline\w*|regret\w*|unfortunately|"
+    # spanish: standalone negation words
+    r"nunca|jam[aá]s|tampoco|ning[uú]n(?:a|o)?|nadie|nada|"
+    # spanish: multi-word negations and rejection stems
+    r"no\s+podemos|no\s+es\s+posible|no\s+acept(?:amos|ar[aá])|"
+    r"rechaz\w*|lamentablemente|descartad\w*|"
+    r"no\s+ha\s+sido\s+aprobad\w*|no\s+procede)\b",
     re.I,
 )
 
@@ -34,11 +41,24 @@ _RULES: list[tuple[MailClassification, re.Pattern[str], float]] = [
         re.compile(r"\b(declin|reject|not able to|unable to|we regret|won.t be able)\w*", re.I),  # noqa: E501
         0.9,
     ),
+    (
+        MailClassification.REJECTION,
+        # spanish rejections (strong stems, not just negation words)
+        re.compile(r"\b(rechaz\w*|no\s+vamos\s+a\s+pod(?:er|emos)|su\s+solicitud\s+ha\s+sido\s+denegada|no\s+cumple\s+los\s+requisitos)\b", re.I),  # noqa: E501
+        0.9,
+    ),
     (
         MailClassification.APPROVAL,
         re.compile(r"\b(approv|accept|welcome to the|you.re (in|approved)|live|activated|glad to)\w*", re.I),  # noqa: E501
         0.85,
     ),
+    (
+        MailClassification.APPROVAL,
+        # spanish approvals (standalone positive stems; the veto still
+        # downgrades if ANY negation appears elsewhere in the mail)
+        re.compile(r"\b(aprob\w*|aceptad\w*|bienvenid\w*|ha\s+sido\s+aceptada|encantados?\s+de\s+(trabajar|colaborar))\b", re.I),  # noqa: E501
+        0.85,
+    ),
     (
         MailClassification.QUESTION,
         re.compile(r"\b(could you|can you|please (provide|clarify|confirm)|what (is|are)|how (do|does|can)|need more (info|details))\b", re.I),  # noqa: E501

tests/test_spanish_negations.py

@@ -0,0 +1,80 @@
+"""Spanish negation tests (round-3 point 4): merchants write in Spanish;
+negations like 'nunca', 'lamentablemente' or 'no podemos' must veto
+`approval` exactly like their English counterparts. Veto rule unchanged:
+when in doubt -> needs_review."""
+
+from __future__ import annotations
+
+import pytest
+
+from cayceops.components.maild import classify as clf
+from cayceops.models import MailClassification
+
+APPROVAL_ONLY = MailClassification.APPROVAL
+
+
+def _never_approval(cfg_factory, text: str) -> None:
+    kind, _ = clf.classify(text, cfg_factory())
+    assert kind is not APPROVAL_ONLY, f"{text!r} classified as APPROVAL"
+
+
+def test_english_baseline_still_works(cfg):
+    config = cfg()
+    kind, _ = clf.classify("Your application was approved, welcome to the program", config)
+    assert kind is APPROVAL_ONLY
+
+
+@pytest.mark.parametrize(
+    "text",
+    [
+        # 1. rejection stem
+        "Lamentamos informarle que su solicitud fue rechazada",
+        # 2. nunca
+        "Nunca aceptamos negocios de criptomonedas",
+        # 3. jamás
+        "Jamás hemos trabajado con affiliates externos",
+        # 4. tampoco
+        "No podemos aceptar su sitio, tampoco podemos ofrecerle otro acuerdo",
+        # 5. ningún/ninguna
+        "En este momento no tenemos ningún hueco para nuevos partners",
+        # 6. no podemos (multi-word)
+        "Su propuesta es interesante pero no podemos proceder",
+        # 7. no es posible (multi-word)
+        "Gracias por escribir, pero no es posible colaborar este trimestre",
+        # 8. lamentablemente
+        "Lamentablemente su aplicación no ha sido aprobada",
+        # 9. no aceptamos
+        "Por política interna no aceptamos sitios de viajes",
+        # 10. mixed spanish/english: negation in spanish, approval word in english
+        "Thanks for reaching out! Lamentablemente we cannot approve your site",
+        # 11. mixed: approval in spanish, negation in english
+        "Apreciamos su interés, but we are not accepting new partners",
+        # 12. nadie / nada
+        "Aquí nadie decidiría eso, así que no hay nada que aprobar",
+    ],
+)
+def test_spanish_and_mixed_negations_veto_approval(cfg, text):
+    _never_approval(cfg, text)
+
+
+def test_spanish_pure_approval_still_approves(cfg):
+    """A clean Spanish approval WITHOUT any negation must still classify
+    approval — the veto must not over-fire."""
+    config = cfg()
+    kind, confidence = clf.classify(
+        "Su solicitud fue aprobada. Bienvenido al programa, estamos encantados "
+        "de trabajar con ustedes.",
+        config,
+    )
+    assert kind is APPROVAL_ONLY
+    assert confidence >= 0.5
+
+
+def test_spanish_rejection_classifies_rejection(cfg):
+    config = cfg()
+    kind, conf = clf.classify(
+        "Lamentamos informarle que su solicitud fue rechazada por el comité",
+        config,
+    )
+    assert kind is MailClassification.REJECTION
+    assert conf >= 0.9