feat: mode hybride Ollama — gemma3:27b pour CPAM, 12b pour codage

Le pipeline utilise désormais gemma3:12b (rapide) pour le codage CIM-10
et gemma3:27b (meilleur raisonnement) pour la contre-argumentation CPAM.
Configurable via OLLAMA_MODEL_CPAM et OLLAMA_TIMEOUT_CPAM.

Inclut aussi : traçabilité source/page DAS, niveaux CMA ATIH, sévérité,
page tracker PDF, améliorations fusion et filtres DAS.

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

tests/test_page_tracker.py

@@ -0,0 +1,95 @@
+"""Tests pour le module PageTracker (traçabilité source)."""
+
+import pytest
+
+from src.extraction.page_tracker import PageTracker
+
+
+class TestCharToPage:
+    def test_first_page(self):
+        pt = PageTracker([(0, 100), (102, 200)])
+        assert pt.char_to_page(0) == 1
+        assert pt.char_to_page(50) == 1
+        assert pt.char_to_page(99) == 1
+
+    def test_second_page(self):
+        pt = PageTracker([(0, 100), (102, 200)])
+        assert pt.char_to_page(102) == 2
+        assert pt.char_to_page(150) == 2
+
+    def test_beyond_last_page(self):
+        pt = PageTracker([(0, 100), (102, 200)])
+        assert pt.char_to_page(300) == 2
+
+    def test_single_page(self):
+        pt = PageTracker([(0, 500)])
+        assert pt.char_to_page(250) == 1
+
+    def test_empty_offsets(self):
+        pt = PageTracker([])
+        assert pt.char_to_page(0) == 1
+
+
+class TestFindPageForText:
+    def _make_tracker(self):
+        """Simule un document 3 pages."""
+        page1 = "Pancréatite aiguë biliaire"
+        page2 = "Cholécystectomie par coelioscopie"
+        page3 = "TTT de sortie: Augmentin IV"
+        sep = "\n\n"
+        full = sep.join([page1, page2, page3])
+
+        offsets = []
+        offset = 0
+        for text in [page1, page2, page3]:
+            offsets.append((offset, offset + len(text)))
+            offset += len(text) + len(sep)
+
+        return PageTracker(offsets), full
+
+    def test_exact_match_page1(self):
+        pt, full = self._make_tracker()
+        assert pt.find_page_for_text("Pancréatite", full) == 1
+
+    def test_exact_match_page2(self):
+        pt, full = self._make_tracker()
+        assert pt.find_page_for_text("Cholécystectomie", full) == 2
+
+    def test_exact_match_page3(self):
+        pt, full = self._make_tracker()
+        assert pt.find_page_for_text("Augmentin", full) == 3
+
+    def test_case_insensitive(self):
+        pt, full = self._make_tracker()
+        assert pt.find_page_for_text("pancréatite", full) == 1
+
+    def test_not_found(self):
+        pt, full = self._make_tracker()
+        assert pt.find_page_for_text("inexistant", full) is None
+
+    def test_empty_text(self):
+        pt, full = self._make_tracker()
+        assert pt.find_page_for_text("", full) is None
+
+
+class TestExtractExcerpt:
+    def test_returns_excerpt(self):
+        text = "A" * 200 + "Pancréatite aiguë" + "B" * 200
+        pt = PageTracker([(0, len(text))])
+        excerpt = pt.extract_excerpt("Pancréatite aiguë", text, context_chars=50)
+        assert excerpt is not None
+        assert "Pancréatite aiguë" in excerpt
+        assert excerpt.startswith("...")
+        assert excerpt.endswith("...")
+
+    def test_at_start(self):
+        text = "Pancréatite aiguë biliaire " + "X" * 200
+        pt = PageTracker([(0, len(text))])
+        excerpt = pt.extract_excerpt("Pancréatite", text, context_chars=50)
+        assert excerpt is not None
+        assert not excerpt.startswith("...")
+
+    def test_not_found(self):
+        text = "Texte sans rapport"
+        pt = PageTracker([(0, len(text))])
+        assert pt.extract_excerpt("inexistant", text) is None