Complete history archive support for dashboard/map data and mark task finished

Add source=archive option for dashboard endpoints and history service; update Docs/Tasks.md; include archive branch for list_bans, bans_by_country, ban_trend, bans_by_jail; tests for archive paths.

backend/tests/test_routers/test_dashboard.py

@@ -290,6 +290,17 @@ class TestDashboardBans:
         called_range = mock_list.call_args[0][1]
         assert called_range == "7d"
 
+    async def test_accepts_source_param(
+        self, dashboard_client: AsyncClient
+    ) -> None:
+        """The ``source`` query parameter is forwarded to ban_service."""
+        mock_list = AsyncMock(return_value=_make_ban_list_response())
+        with patch("app.routers.dashboard.ban_service.list_bans", new=mock_list):
+            await dashboard_client.get("/api/dashboard/bans?source=archive")
+
+        called_source = mock_list.call_args[1]["source"]
+        assert called_source == "archive"
+
     async def test_empty_ban_list_returns_zero_total(
         self, dashboard_client: AsyncClient
     ) -> None:
@@ -492,6 +503,16 @@ class TestDashboardBansOriginField:
         origins = {ban["origin"] for ban in bans}
         assert origins == {"blocklist", "selfblock"}
 
+    async def test_bans_by_country_source_param_forwarded(
+        self, dashboard_client: AsyncClient
+    ) -> None:
+        """The ``source`` query parameter is forwarded to bans_by_country."""
+        mock_fn = AsyncMock(return_value=_make_bans_by_country_response())
+        with patch("app.routers.dashboard.ban_service.bans_by_country", new=mock_fn):
+            await dashboard_client.get("/api/dashboard/bans/by-country?source=archive")
+
+        assert mock_fn.call_args[1]["source"] == "archive"
+
     async def test_blocklist_origin_serialised_correctly(
         self, dashboard_client: AsyncClient
     ) -> None: