[FIX] tab6: source resource list from resource_usage (not resource_caps) to include custom batches, fix resource usage computation, remove broken CSV export

tabs/tab6_scenarios.py

@@ -58,9 +58,14 @@ def prepare_comparison_data(selected):
         m for name in selected
         for m in st.session_state.scenarios[name].get("allocations", {})
     })
+    # Built from the stored resource_usage keys (not resource_caps): a custom
+    # batch pooled with a standard resource (e.g. "Basalt A" complementing
+    # "Basalt mineral") is never added to resource_caps — only resource_usage
+    # tracks it — so sourcing the list from resource_caps would silently drop
+    # every such batch from the comparison entirely.
     all_resources = sorted({
         r for name in selected
-        for r in st.session_state.scenarios[name].get("resource_caps", {})
+        for r in st.session_state.scenarios[name].get("resource_usage", {})
         if r not in hidden_resource_names
     })
 
@@ -69,7 +74,11 @@ def prepare_comparison_data(selected):
     for name in selected:
         scenario = st.session_state.scenarios[name]
         allocations = scenario.get("allocations", {})
-        method_costs = scenario.get("method_costs", {})  # ← fix: was using method_constraints
+        # Use the resource_usage already computed by the LP at save time —
+        # NOT a recomputation from method_costs × allocations, which double-
+        # counts standard resources that are pooled with a custom batch (the
+        # LP only attributes the standard's own share to it, not the batch's).
+        resource_usage = scenario.get("resource_usage", {})
 
         row = {
             "Scenario": name,
@@ -82,10 +91,9 @@ def prepare_comparison_data(selected):
             method_alloc_rows.append({"Scenario": name, "Method": method, f"{CO2_UNIT}": val})
 
         for resource in all_resources:
-            total_used = 0
-            for method, tco2 in allocations.items():
-                used = method_costs.get(method, {}).get(resource, 0) * tco2
-                total_used += used
+            per_method = resource_usage.get(resource, {})
+            total_used = sum(per_method.values())
+            for method, used in per_method.items():
                 if used > 0:
                     resource_usage_rows.append({
                         "Scenario": name, "Method": method,
@@ -180,7 +188,7 @@ def render_tab():
         with col1:
             st.markdown(f"**{name}**")
         with col2:
-            if st.button("❌", key=f"remove_{name}"):
+            if st.button(label="", key=f"remove_{name}", icon=":material/delete:", help=f"Remove scenario {name} from comparison"):
                 st.session_state.scenarios.pop(name, None)
                 st.rerun()
 
@@ -193,12 +201,6 @@ def render_tab():
 
     st.markdown("""<p class="crra-sub-heading">Summary Table</p>""", unsafe_allow_html=True)
     st.dataframe(df_summary.style.format(na_rep="-", thousands=","), width='stretch')
-    st.download_button(
-        "Export Comparison CSV",
-        df_summary.to_csv(index=False).encode("utf-8"),
-        "scenario_comparison.csv", "text/csv",
-        icon=":material/download:"
-    )
 
     show_method_allocations(df_methods)
     show_resource_usage(df_resources)