Update UI, and Update Sitemap tool to get proper thread count

app.py

@@ -61,6 +61,8 @@ def render_sitemap_tab() -> None:
     st.caption("Crawl a site, export a sitemap CSV, and keep resume data inside the container data volume.")
 
     SITEMAP_OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
+    sitemap_builder = get_sitemap_module()
+    default_workers = sitemap_builder.DEFAULT_WORKERS
 
     with st.form("sitemap-form"):
         start_url = st.text_input("Starting URL", placeholder="https://example.com")
@@ -73,7 +75,13 @@ def render_sitemap_tab() -> None:
         col1, col2, col3 = st.columns(3)
         with col1:
             max_pages = st.number_input("Max pages", min_value=1, value=10000, step=100)
-            workers = st.number_input("Worker threads", min_value=1, value=8, step=1)
+            workers = st.number_input(
+                "Worker threads",
+                min_value=1,
+                value=default_workers,
+                step=1,
+                help="Defaults to the number of CPUs visible inside the Docker container.",
+            )
         with col2:
             delay = st.number_input("Delay between requests (seconds)", min_value=0.0, value=0.0, step=0.25)
             timeout = st.number_input("Request timeout (seconds)", min_value=1.0, value=15.0, step=1.0)
@@ -90,7 +98,6 @@ def render_sitemap_tab() -> None:
         if not start_url.strip():
             st.error("Starting URL is required.")
         else:
-            sitemap_builder = get_sitemap_module()
             safe_name = sanitize_job_name(job_name)
             output_path = SITEMAP_OUTPUT_DIR / f"{safe_name}.csv"
             captured_stdout = io.StringIO()
@@ -137,7 +144,6 @@ def render_sitemap_tab() -> None:
         st.info("Run a crawl to generate a sitemap CSV.")
         return
 
-    sitemap_builder = get_sitemap_module()
     summary = result_data["summary"]
     csv_path = Path(result_data["output_path"])
     state_path = Path(result_data["state_path"])