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