fix: make default table_mode configurable via DEFAULT_TABLE_MODE (H1)

TableFormerMode.ACCURATE is very expensive on CPU (~3-5x slower).
The default can now be set to "fast" on resource-constrained
environments (HF Spaces) via the DEFAULT_TABLE_MODE env var.

User-specified table_mode in the request still takes precedence.

Ref #57 (H1)

document-parser/infra/settings.py

@@ -16,6 +16,7 @@ class Settings:
     conversion_timeout: int = 900
     document_timeout: float = 120.0  # Docling-level per-document timeout (seconds)
     max_concurrent_analyses: int = 3
+    default_table_mode: str = "accurate"  # "accurate" or "fast"
     max_page_count: int = 0  # 0 = unlimited (upload validation)
     max_file_size: int = 0  # 0 = unlimited (Docling-level, bytes)
     upload_dir: str = "./uploads"
@@ -37,6 +38,7 @@ class Settings:
             conversion_timeout=int(os.environ.get("CONVERSION_TIMEOUT", "900")),
             document_timeout=float(os.environ.get("DOCUMENT_TIMEOUT", "120.0")),
             max_concurrent_analyses=int(os.environ.get("MAX_CONCURRENT_ANALYSES", "3")),
+            default_table_mode=os.environ.get("DEFAULT_TABLE_MODE", "accurate"),
             max_page_count=int(os.environ.get("MAX_PAGE_COUNT", "0")),
             max_file_size=int(os.environ.get("MAX_FILE_SIZE", "0")),
             upload_dir=os.environ.get("UPLOAD_DIR", "./uploads"),

document-parser/services/analysis_service.py

@@ -15,6 +15,7 @@ from typing import TYPE_CHECKING
 
 from domain.models import AnalysisJob, AnalysisStatus
 from domain.value_objects import ChunkingOptions, ChunkResult, ConversionOptions, ConversionResult
+from infra.settings import settings
 
 if TYPE_CHECKING:
     from domain.ports import DocumentChunker, DocumentConverter
@@ -151,7 +152,10 @@ class AnalysisService:
             await analysis_repo.update_status(job)
             logger.info("Analysis started: %s (file: %s)", job_id, filename)
 
-            options = ConversionOptions(**(pipeline_options or {}))
+            opts_dict = pipeline_options or {}
+            if "table_mode" not in opts_dict:
+                opts_dict = {**opts_dict, "table_mode": settings.default_table_mode}
+            options = ConversionOptions(**opts_dict)
 
             result: ConversionResult = await asyncio.wait_for(
                 self._converter.convert(file_path, options),