feat: T2A-Extractor pipeline with CIM-10 normalizer (31→0 warnings)

Initial commit with full extraction pipeline: PDF OCR (docTR), text
segmentation, LLM extraction (Ollama), deterministic post-processing
normalizer, validation, and Excel/CSV export.

The normalizer fixes OCR/LLM errors on CIM-10 codes:
- OCR digit→letter confusion in position 1 (1→I, 0→O, 5→S, 2→Z, 8→B)
- Missing dot separator (F050→F05.0, R410→R41.0)
- '+' instead of '.' (B99+1→B99.1, J961+0→J96.10)
- Excess decimals (Z04.880→Z04.88)
- OCR letter→digit in positions 2-3 (LO2.2→L02.2)
- Literal "null" string purge
- Auto-fill codes_retenus from decision context

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

extractor/__init__.py

@@ -0,0 +1,6 @@
+import sys
+from pathlib import Path
+
+_project_root = str(Path(__file__).resolve().parent.parent)
+if _project_root not in sys.path:
+    sys.path.insert(0, _project_root)