Add professional SVG chart generation with Kerykeion 5.x

✨ New features:
- POST /api/generate-chart-svg endpoint
- Uses ChartDataFactory + ChartDrawer for professional visualization
- Includes aspects (相位线) and proper planet placement
- Returns SVG that can be directly embedded in frontend

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app.py

@@ -5,10 +5,14 @@ Just returns raw Kerykeion calculations
 
 from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import Response
 from pydantic import BaseModel
-from kerykeion import AstrologicalSubject
+from kerykeion import AstrologicalSubject, AstrologicalSubjectFactory
+from kerykeion.chart_data_factory import ChartDataFactory
+from kerykeion.charts.chart_drawer import ChartDrawer
 from typing import Optional, Any, Dict
 import logging
+import io
 
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
@@ -118,6 +122,65 @@ async def calculate_chart(req: BirthRequest):
         logger.error(f"❌ Error: {e}")
         raise HTTPException(status_code=500, detail=str(e))
 
+
+@app.post("/api/generate-chart-svg")
+async def generate_chart_svg(req: BirthRequest):
+    """Generate professional birth chart SVG with aspects"""
+    try:
+        logger.info(f"🎨 Generating SVG chart for: {req.name}")
+
+        year, month, day = map(int, req.date.split('-'))
+        hour, minute = map(int, req.time.split(':'))
+
+        # Use new Kerykeion 5.x API
+        subject = AstrologicalSubjectFactory.from_birth_data(
+            name=req.name,
+            year=year, month=month, day=day,
+            hour=hour, minute=minute,
+            lng=req.longitude or 0.0,
+            lat=req.latitude or 0.0,
+            tz_str=req.timezone,
+            zodiac_type="Tropic",
+            houses_system_identifier="P",
+            online=False
+        )
+
+        # Create chart data
+        chart_data = ChartDataFactory.create_natal_chart_data(subject)
+
+        # Generate SVG
+        chart_drawer = ChartDrawer(chart_data=chart_data)
+
+        # Get SVG content (ChartDrawer internally generates SVG)
+        # We need to save to a temp location then read it
+        import tempfile
+        from pathlib import Path
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            output_path = Path(tmpdir)
+            chart_drawer.save_svg(output_path=output_path, filename="chart")
+
+            svg_file = output_path / "chart.svg"
+            if not svg_file.exists():
+                raise HTTPException(status_code=500, detail="Failed to generate SVG")
+
+            svg_content = svg_file.read_text()
+
+        logger.info(f"✅ SVG generated for {req.name}")
+
+        return Response(
+            content=svg_content,
+            media_type="image/svg+xml",
+            headers={
+                "Content-Disposition": f'inline; filename="{req.name}-chart.svg"'
+            }
+        )
+
+    except Exception as e:
+        logger.error(f"❌ SVG Error: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
 if __name__ == "__main__":
     import uvicorn
     # Hugging Face Spaces requires port 7860