feat: create PARSER service skeleton with FastAPI

- Create parser-service/ with full structure
- Add FastAPI app with endpoints (/parse, /parse_qa, /parse_markdown, /parse_chunks)
- Add Pydantic schemas (ParsedDocument, ParsedBlock, ParsedChunk, etc.)
- Add runtime module with model_loader and inference (with dummy parser)
- Add configuration, Dockerfile, requirements.txt
- Update TODO-PARSER-RAG.md with completed tasks
- Ready for dots.ocr model integration

services/parser-service/app/core/config.py

@@ -0,0 +1,38 @@
+"""
+Configuration for PARSER Service
+"""
+
+import os
+from typing import Literal
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    """Application settings"""
+    
+    # Service
+    API_HOST: str = "0.0.0.0"
+    API_PORT: int = 9400
+    
+    # PARSER Model
+    PARSER_MODEL_NAME: str = os.getenv("PARSER_MODEL_NAME", "rednote-hilab/dots.ocr")
+    PARSER_DEVICE: Literal["cuda", "cpu", "mps"] = os.getenv("PARSER_DEVICE", "cpu")
+    PARSER_MAX_PAGES: int = int(os.getenv("PARSER_MAX_PAGES", "100"))
+    PARSER_MAX_RESOLUTION: str = os.getenv("PARSER_MAX_RESOLUTION", "4096x4096")
+    PARSER_BATCH_SIZE: int = int(os.getenv("PARSER_BATCH_SIZE", "1"))
+    
+    # File handling
+    MAX_FILE_SIZE_MB: int = int(os.getenv("MAX_FILE_SIZE_MB", "50"))
+    TEMP_DIR: str = os.getenv("TEMP_DIR", "/tmp/parser")
+    
+    # Runtime
+    RUNTIME_TYPE: Literal["local", "remote"] = os.getenv("RUNTIME_TYPE", "local")
+    RUNTIME_URL: str = os.getenv("RUNTIME_URL", "http://parser-runtime:11435")
+    
+    class Config:
+        env_file = ".env"
+        case_sensitive = True
+
+
+settings = Settings()
+