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/schemas.py

@@ -0,0 +1,108 @@
+"""
+Pydantic schemas for PARSER Service
+"""
+
+from typing import Optional, List, Dict, Any, Literal
+from pydantic import BaseModel, Field
+from datetime import datetime
+
+
+class BBox(BaseModel):
+    """Bounding box coordinates"""
+    x: float = Field(..., description="X coordinate")
+    y: float = Field(..., description="Y coordinate")
+    width: float = Field(..., description="Width")
+    height: float = Field(..., description="Height")
+
+
+class TableCell(BaseModel):
+    """Table cell data"""
+    row: int
+    col: int
+    text: str
+    rowspan: Optional[int] = 1
+    colspan: Optional[int] = 1
+
+
+class TableData(BaseModel):
+    """Structured table data"""
+    rows: List[List[str]] = Field(..., description="Table rows")
+    columns: List[str] = Field(..., description="Column headers")
+    merged_cells: Optional[List[Dict[str, Any]]] = Field(None, description="Merged cells info")
+
+
+class ParsedBlock(BaseModel):
+    """Parsed document block"""
+    type: Literal["paragraph", "heading", "table", "formula", "figure_caption", "list"] = Field(
+        ..., description="Block type"
+    )
+    text: str = Field(..., description="Block text content")
+    bbox: BBox = Field(..., description="Bounding box")
+    reading_order: int = Field(..., description="Reading order index")
+    page_num: int = Field(..., description="Page number")
+    table_data: Optional[TableData] = Field(None, description="Table data (if type=table)")
+    metadata: Optional[Dict[str, Any]] = Field(None, description="Additional metadata")
+
+
+class ParsedPage(BaseModel):
+    """Parsed document page"""
+    page_num: int = Field(..., description="Page number (1-indexed)")
+    blocks: List[ParsedBlock] = Field(..., description="Page blocks")
+    width: float = Field(..., description="Page width in pixels")
+    height: float = Field(..., description="Page height in pixels")
+
+
+class ParsedChunk(BaseModel):
+    """Semantic chunk for RAG"""
+    text: str = Field(..., description="Chunk text")
+    page: int = Field(..., description="Page number")
+    bbox: Optional[BBox] = Field(None, description="Bounding box")
+    section: Optional[str] = Field(None, description="Section name")
+    metadata: Dict[str, Any] = Field(default_factory=dict, description="Additional metadata")
+
+
+class QAPair(BaseModel):
+    """Question-Answer pair"""
+    question: str = Field(..., description="Question")
+    answer: str = Field(..., description="Answer")
+    source_page: int = Field(..., description="Source page number")
+    source_bbox: Optional[BBox] = Field(None, description="Source bounding box")
+    confidence: Optional[float] = Field(None, description="Confidence score")
+
+
+class ParsedDocument(BaseModel):
+    """Complete parsed document"""
+    doc_id: Optional[str] = Field(None, description="Document ID")
+    doc_url: Optional[str] = Field(None, description="Document URL")
+    doc_type: Literal["pdf", "image"] = Field(..., description="Document type")
+    pages: List[ParsedPage] = Field(..., description="Parsed pages")
+    metadata: Dict[str, Any] = Field(default_factory=dict, description="Document metadata")
+    created_at: datetime = Field(default_factory=datetime.utcnow, description="Creation timestamp")
+
+
+class ParseRequest(BaseModel):
+    """Parse request"""
+    doc_url: Optional[str] = Field(None, description="Document URL")
+    output_mode: Literal["raw_json", "markdown", "qa_pairs", "chunks"] = Field(
+        "raw_json", description="Output mode"
+    )
+    dao_id: Optional[str] = Field(None, description="DAO ID")
+    doc_id: Optional[str] = Field(None, description="Document ID")
+
+
+class ParseResponse(BaseModel):
+    """Parse response"""
+    document: Optional[ParsedDocument] = Field(None, description="Parsed document (raw_json mode)")
+    markdown: Optional[str] = Field(None, description="Markdown content (markdown mode)")
+    qa_pairs: Optional[List[QAPair]] = Field(None, description="QA pairs (qa_pairs mode)")
+    chunks: Optional[List[ParsedChunk]] = Field(None, description="Chunks (chunks mode)")
+    metadata: Dict[str, Any] = Field(default_factory=dict, description="Additional metadata")
+
+
+class ChunksResponse(BaseModel):
+    """Chunks response for RAG"""
+    chunks: List[ParsedChunk] = Field(..., description="Document chunks")
+    total_chunks: int = Field(..., description="Total number of chunks")
+    doc_id: str = Field(..., description="Document ID")
+    dao_id: str = Field(..., description="DAO ID")
+