Add origin field and filter for ban sources (Tasks 1 & 2)

- Task 1: Mark imported blocklist IP addresses
  - Add BanOrigin type and _derive_origin() to ban.py model
  - Populate origin field in ban_service list_bans() and bans_by_country()
  - BanTable and MapPage companion table show origin badge column
  - Tests: origin derivation in test_ban_service.py and test_dashboard.py

- Task 2: Add origin filter to dashboard and world map
  - ban_service: _origin_sql_filter() helper; origin param on list_bans()
    and bans_by_country()
  - dashboard router: optional origin query param forwarded to service
  - Frontend: BanOriginFilter type + BAN_ORIGIN_FILTER_LABELS in ban.ts
  - fetchBans / fetchBansByCountry forward origin to API
  - useBans / useMapData accept and pass origin; page resets on change
  - BanTable accepts origin prop; DashboardPage adds segmented filter
  - MapPage adds origin Select next to time-range picker
  - Tests: origin filter assertions in test_ban_service and test_dashboard

frontend/src/pages/DashboardPage.tsx

@@ -16,8 +16,8 @@ import {
 } from "@fluentui/react-components";
 import { BanTable } from "../components/BanTable";
 import { ServerStatusBar } from "../components/ServerStatusBar";
-import type { TimeRange } from "../types/ban";
-import { TIME_RANGE_LABELS } from "../types/ban";
+import type { BanOriginFilter, TimeRange } from "../types/ban";
+import { BAN_ORIGIN_FILTER_LABELS, TIME_RANGE_LABELS } from "../types/ban";
 
 
 // ---------------------------------------------------------------------------
@@ -73,6 +73,9 @@ const useStyles = makeStyles({
 /** Ordered time-range presets for the toolbar. */
 const TIME_RANGES: TimeRange[] = ["24h", "7d", "30d", "365d"];
 
+/** Ordered origin filter options for the toolbar. */
+const ORIGIN_FILTERS: BanOriginFilter[] = ["all", "blocklist", "selfblock"];
+
 // ---------------------------------------------------------------------------
 // Component
 // ---------------------------------------------------------------------------
@@ -86,6 +89,7 @@ const TIME_RANGES: TimeRange[] = ["24h", "7d", "30d", "365d"];
 export function DashboardPage(): React.JSX.Element {
   const styles = useStyles();
   const [timeRange, setTimeRange] = useState<TimeRange>("24h");
+  const [originFilter, setOriginFilter] = useState<BanOriginFilter>("all");
 
   return (
     <div className={styles.root}>
@@ -119,11 +123,28 @@ export function DashboardPage(): React.JSX.Element {
               </ToggleButton>
             ))}
           </Toolbar>
+
+          {/* Origin filter */}
+          <Toolbar aria-label="Origin filter" size="small">
+            {ORIGIN_FILTERS.map((f) => (
+              <ToggleButton
+                key={f}
+                size="small"
+                checked={originFilter === f}
+                onClick={() => {
+                  setOriginFilter(f);
+                }}
+                aria-pressed={originFilter === f}
+              >
+                {BAN_ORIGIN_FILTER_LABELS[f]}
+              </ToggleButton>
+            ))}
+          </Toolbar>
         </div>
 
         {/* Ban table */}
         <div className={styles.tabContent}>
-          <BanTable timeRange={timeRange} />
+          <BanTable timeRange={timeRange} origin={originFilter} />
         </div>
       </div>
     </div>