Add delete job functionality with confirmation step

Adds DELETE /api/jobs/{id} endpoint (removes DB record and image file),
and a two-step Delete / Confirm button on the review page that returns
to the job list on success.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/main.py

@@ -877,6 +877,39 @@ async def review_job(job_id: str, body: ReviewRequest):
     return JSONResponse(_job_row_to_dict(row))
 
 
+@app.delete("/api/jobs/{job_id}")
+async def delete_job(job_id: str):
+    """Delete a job record and its stored image."""
+    try:
+        uuid.UUID(job_id)
+    except ValueError:
+        raise HTTPException(status_code=400, detail="Invalid job ID.")
+
+    try:
+        with get_db() as conn:
+            with conn.cursor() as cur:
+                cur.execute(
+                    "DELETE FROM ocr_jobs WHERE id = %s RETURNING image_path",
+                    (job_id,),
+                )
+                row = cur.fetchone()
+    except Exception as exc:
+        print(f"delete_job DB error: {exc}")
+        raise HTTPException(status_code=500, detail="Database error.")
+
+    if not row:
+        raise HTTPException(status_code=404, detail="Job not found.")
+
+    # Best-effort removal of the stored image file
+    try:
+        if row["image_path"] and os.path.isfile(row["image_path"]):
+            os.remove(row["image_path"])
+    except Exception:
+        pass
+
+    return JSONResponse({"deleted": job_id})
+
+
 if __name__ == "__main__":
     host = env_config("API_HOST", default="0.0.0.0")
     port = env_config("API_PORT", default=8000, cast=int)