Add PDF-to-JPEG support in web UI and /convert/pdf endpoint

Web UI now accepts both images and PDFs. Images go through /strip
as before; PDFs go through new /convert/pdf endpoint which renders
all pages via pdftoppm and returns base64 JPEGs. Also updates
page title and layout.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -11,9 +11,11 @@ Image/PDF-to-JPEG conversion microservice. Single-file Node.js/Express app (`ser
 
 ## Endpoints
 
+- `GET /` — web UI for stripping photo metadata (drag-and-drop, uses `/strip`)
 - `GET /health` — health check
-- `POST /convert` — image or first PDF page → JPEG
-- `POST /convert/pdf` — all PDF pages → ZIP of JPEGs
+- `POST /strip` — strip metadata from image, return clean JPEG + removed metadata (JSON or raw)
+- `POST /convert` — image or first PDF page → JPEG (resize/quality via headers)
+- `POST /convert/pdf` — all PDF pages → JSON array of base64 JPEGs
 
 ## Auth