feat: filtrage des DAS parasites (artefacts OCR trackare)

Nouveau module das_filter.py avec 7 règles de rejet (trop court, chiffres,
lettre+chiffres OCR, mots concaténés/répétés, fragments non-médicaux) +
nettoyage newlines/ponctuation. Filtrage appliqué aux 3 sources de DAS :
trackare, regex et edsnlp. 31 tests unitaires.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_das_filter.py

@@ -0,0 +1,106 @@
+"""Tests unitaires pour le filtre de DAS parasites."""
+
+import pytest
+
+from src.medical.das_filter import clean_diagnostic_text, is_valid_diagnostic_text
+
+
+class TestCleanDiagnosticText:
+    def test_removes_trailing_punctuation(self):
+        assert clean_diagnostic_text("Thrombopénie,") == "Thrombopénie"
+
+    def test_removes_trailing_semicolon(self):
+        assert clean_diagnostic_text("HTA;") == "HTA"
+
+    def test_replaces_newlines(self):
+        assert clean_diagnostic_text("Insuffisance rénale\naigue") == "Insuffisance rénale aigue"
+
+    def test_strips_whitespace(self):
+        assert clean_diagnostic_text("  HTA  ") == "HTA"
+
+    def test_collapses_multiple_spaces(self):
+        assert clean_diagnostic_text("Insuffisance  rénale   aigue") == "Insuffisance rénale aigue"
+
+    def test_combined_cleanup(self):
+        assert clean_diagnostic_text("  Anticoagulant\nanticoagulant,  ") == "Anticoagulant anticoagulant"
+
+
+class TestIsValidDiagnosticText:
+    # --- Rejets ---
+    def test_reject_empty(self):
+        assert not is_valid_diagnostic_text("")
+
+    def test_reject_too_short(self):
+        assert not is_valid_diagnostic_text("Ab")
+
+    def test_reject_digits_only(self):
+        assert not is_valid_diagnostic_text("666666666666664")
+
+    def test_reject_mostly_digits(self):
+        assert not is_valid_diagnostic_text("12345abc")
+
+    def test_reject_letter_space_digits(self):
+        assert not is_valid_diagnostic_text("H 51")
+
+    def test_reject_letter_space_digits_a_accent(self):
+        assert not is_valid_diagnostic_text("À 08")
+
+    def test_reject_letter_newline_digits(self):
+        # Après clean, "H\n10" devient "H 10"
+        assert not is_valid_diagnostic_text("H 10")
+
+    def test_reject_concatenated_words(self):
+        assert not is_valid_diagnostic_text("Ventilationventilation")
+
+    def test_reject_concatenated_words_long(self):
+        assert not is_valid_diagnostic_text("ventilationventilationventilation")
+
+    def test_reject_repeated_words(self):
+        assert not is_valid_diagnostic_text("Spontanée spontanée spontanée spontanée")
+
+    def test_reject_repeated_words_three(self):
+        assert not is_valid_diagnostic_text("oui oui oui")
+
+    def test_reject_fragment_de(self):
+        assert not is_valid_diagnostic_text("De laboratoire")
+
+    def test_reject_fragment_du(self):
+        assert not is_valid_diagnostic_text("Du sang")
+
+    def test_reject_fragment_des(self):
+        assert not is_valid_diagnostic_text("Des résultats")
+
+    def test_reject_bracket_fragment(self):
+        assert not is_valid_diagnostic_text("] de laboratoire")
+
+    def test_reject_isolement(self):
+        assert not is_valid_diagnostic_text("Isolement")
+
+    def test_reject_pp_marker(self):
+        assert not is_valid_diagnostic_text("Pp 500")
+
+    # --- Acceptations ---
+    def test_accept_hta(self):
+        assert is_valid_diagnostic_text("HTA")
+
+    def test_accept_cholecystite(self):
+        assert is_valid_diagnostic_text("Cholécystite aiguë")
+
+    def test_accept_lithiase(self):
+        assert is_valid_diagnostic_text("Lithiase vésiculaire")
+
+    def test_accept_insuffisance_renale(self):
+        assert is_valid_diagnostic_text("Insuffisance rénale aigue")
+
+    def test_accept_obesite_with_imc(self):
+        assert is_valid_diagnostic_text("Obésité (IMC 35.251)")
+
+    def test_accept_short_valid(self):
+        # 3 chars = seuil exact, doit passer
+        assert is_valid_diagnostic_text("HTA")
+
+    def test_accept_diabete(self):
+        assert is_valid_diagnostic_text("Diabète de type 2")
+
+    def test_accept_sepsis(self):
+        assert is_valid_diagnostic_text("Sepsis sévère")