fix: resolve report_url=None for blob-URL tickers and fix dataclass serialization

When Schwab uses modern blob URLs (increasingly common), find_report()
returns __CLICK_TO_OPEN__ and the scraper skips storing a report_url
even though the PDF downloads and parses successfully. This caused
agents to see report_url=None for tickers like PEP/BR/DPZ/MSCI/BMI.

Changes:
- Fix serialize() to use dataclasses.asdict() instead of str() for
  dataclass payloads, producing proper JSON objects instead of Python
  repr strings
- Add /reports/{ticker}/pdf endpoint to serve cached Morningstar PDFs
- Enrich report_url with the MCP's own PDF endpoint when blob URLs
  were used and the report was successfully downloaded
- Add SCHWAB_MCP_BASE_URL env var to compose for self-referential URLs

compose.yaml

@@ -22,6 +22,7 @@ services:
           cpus: '0.1'
     environment:
       - SCHWAB_PLAYWRIGHT_URL=ws://browser.local.ben.io:3000/playwright/chromium?timeout=300000
+      - SCHWAB_MCP_BASE_URL=https://schwab-mcp.ext.ben.io
       - PORT=8000
     volumes:
       - ./cookies.json:/app/cookies.json

server.py

@@ -1,3 +1,4 @@
+import dataclasses
 import io
 import json
 import logging
@@ -9,11 +10,12 @@ from typing import Optional, Any, Tuple
 
 from fastmcp import FastMCP
 from starlette.applications import Starlette
-from starlette.responses import JSONResponse
+from starlette.responses import JSONResponse, Response
 from starlette.routing import Route, Mount
 import uvicorn
 
 import schwab_scraper.unified_api as api
+from schwab_scraper.storage.cache import read_cached_pdf
 
 
 # ---------------------------------------------------------------------------
@@ -236,18 +238,25 @@ login_manager = LoginManager()
 mcp = FastMCP("SchwabScraper")
 
 
+def _json_default(obj: Any) -> Any:
+    """JSON fallback handler that converts dataclasses to dicts before str()."""
+    if dataclasses.is_dataclass(obj) and not isinstance(obj, type):
+        return dataclasses.asdict(obj)
+    return str(obj)
+
+
 def serialize(obj: Any) -> str:
     """Safely serialize Pydantic models or dataclasses to JSON string."""
     if hasattr(obj, "model_dump_json"):
         return obj.model_dump_json()
     elif hasattr(obj, "model_dump"):
-        return json.dumps(obj.model_dump(), default=str)
+        return json.dumps(obj.model_dump(), default=_json_default)
     elif isinstance(obj, list):
         return json.dumps([
             o.model_dump() if hasattr(o, "model_dump") else o
             for o in obj
-        ], default=str)
-    return json.dumps(obj, default=str)
+        ], default=_json_default)
+    return json.dumps(obj, default=_json_default)
 
 
 # ---------------------------------------------------------------------------
@@ -457,6 +466,21 @@ async def get_morningstar_data(ticker: str, debug: bool = False) -> str:
         debug: Enable debug logging
     """
     result = await api.get_morningstar_data(ticker, debug=debug)
+
+    # When the scraper used blob URLs (modern Schwab web components), report_url
+    # is None even though the PDF was downloaded and parsed successfully.  Point
+    # callers at the MCP server's cached-PDF endpoint instead.
+    if (
+        isinstance(result, dict)
+        and result.get("success")
+        and result.get("data") is not None
+    ):
+        data = result["data"]
+        if hasattr(data, "report_url") and data.report_url is None and data.source is not None:
+            base = os.getenv("SCHWAB_MCP_BASE_URL", "").rstrip("/")
+            if base:
+                data.report_url = f"{base}/reports/{ticker.upper()}/pdf"
+
     return serialize(result)
 
 
@@ -527,10 +551,27 @@ async def health(request):
     return JSONResponse({"status": "ok"})
 
 
+async def serve_report_pdf(request):
+    """Serve a cached Morningstar report PDF by ticker."""
+    ticker = request.path_params["ticker"].upper()
+    pdf_bytes = read_cached_pdf(ticker)
+    if not pdf_bytes:
+        return JSONResponse(
+            {"error": f"No cached report for {ticker}. Call get_morningstar_data first."},
+            status_code=404,
+        )
+    return Response(
+        pdf_bytes,
+        media_type="application/pdf",
+        headers={"Content-Disposition": f'inline; filename="{ticker}_morningstar.pdf"'},
+    )
+
+
 mcp_app = mcp.http_app()
 app = Starlette(
     routes=[
         Route("/health", health),
+        Route("/reports/{ticker}/pdf", serve_report_pdf),
         Mount("/", app=mcp_app),
     ],
     lifespan=mcp_app.lifespan,