feat(fusion_accounting_ocr): pluggable OCR for vendor bills

Replaces Enterprise's account_invoice_extract with a Fusion-native pipeline:

Stage 1 (text extraction): Tesseract OCRs the bill attachment via
pytesseract + pdf2image. Pluggable OCRProvider adapter pattern allows
future Mindee / Google Document AI / Ollama-vision backends.

Stage 2 (field parsing): The fusion_accounting_ai LLMProvider reads the
raw OCR text and returns structured invoice fields (vendor, invoice
number, dates, amounts, line items) as JSON.

Draft invoice fields are auto-populated for empty-only fields (never
overwriting user-entered data). Vendor matching by name against
res.partner with supplier_rank > 0.

Adds:
- account.move.ocr_state (selection: not_requested/pending/processing/
  done/failed/manual)
- account.move.ocr_raw_text, ocr_extracted_data (Json), ocr_backend,
  ocr_confidence
- fusion.ocr.log (audit trail per OCR run)
- res.company.fusion_ocr_enabled / fusion_ocr_default_backend / auto_run
- /fusion/ocr/request_for_invoice JSON-RPC endpoint

Backend availability detected at runtime via OCRProvider.is_available()
classmethods. Tesseract 5.3.4 + pytesseract 0.3.13 + pdf2image 1.17.0
are installed in the container.

Tests: 13 (TesseractAdapter availability + image OCR; flow tests for
draft autofill, no-attachment guard, customer-invoice guard, ref-not-
overwritten; field parser empty/clean-json/markdown-fence/bad-JSON/
provider-exception). All pass on westin-v19 OrbStack VM.

Made-with: Cursor

fusion_accounting_ocr/__manifest__.py

@@ -0,0 +1,39 @@
+{
+    'name': 'Fusion Accounting — Invoice OCR',
+    'version': '19.0.1.0.0',
+    'category': 'Accounting/Accounting',
+    'summary': 'OCR for vendor bills via tesseract + LLM-driven field extraction.',
+    'description': """
+Fusion Accounting — Invoice OCR
+================================
+Replaces Enterprise's account_invoice_extract with a Fusion-native pipeline:
+
+1. Tesseract OCRs the bill attachment (PDF or image) into raw text
+2. The fusion_accounting_ai LLMProvider parses the raw text into structured
+   fields (vendor, invoice number, dates, amounts, line items)
+3. Draft invoice fields are populated for the AP user to confirm
+
+Pluggable backend architecture: future Mindee, Google Document AI, or
+Ollama-vision adapters can be dropped in alongside the default tesseract
+adapter.
+""",
+    'icon': '/fusion_accounting_ocr/static/description/icon.png',
+    'author': 'Westin / Fusion Suite',
+    'depends': [
+        'fusion_accounting_core',
+        'fusion_accounting_ai',
+        'account',
+    ],
+    'external_dependencies': {
+        'python': ['pytesseract', 'pdf2image', 'PIL'],
+    },
+    'data': [
+        'security/ir.model.access.csv',
+        'views/account_move_views.xml',
+        'views/res_config_settings_views.xml',
+    ],
+    'auto_install': False,
+    'installable': True,
+    'application': False,
+    'license': 'LGPL-3',
+}