feat(issues): load all open issues without limit, paginate closed (#459)

- Add ListOpenIssues SQL query (excludes done/cancelled, no LIMIT)
- Add CountIssues SQL query for true total count
- Backend: support open_only=true param, fix total to return real count
- Frontend: two-phase fetch in issue store (all open + first 50 closed)
- Add fetchMoreClosed action for paginated closed issue loading
- Replace all hardcoded limit:200 with store.fetch() calls

Resolves MUL-369

Co-authored-by: Devv <devv@Devvs-Mac-mini.local>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/features/issues/components/batch-action-toolbar.tsx

@@ -53,9 +53,7 @@ export function BatchActionToolbar() {
       toast.success(`Updated ${count} issue${count > 1 ? "s" : ""}`);
     } catch {
       toast.error("Failed to update issues");
-      api.listIssues({ limit: 200 }).then((res) => {
-        useIssueStore.getState().setIssues(res.issues);
-      }).catch(console.error);
+      useIssueStore.getState().fetch().catch(console.error);
     } finally {
       setLoading(false);
     }
@@ -72,9 +70,7 @@ export function BatchActionToolbar() {
       toast.success(`Deleted ${count} issue${count > 1 ? "s" : ""}`);
     } catch {
       toast.error("Failed to delete issues");
-      api.listIssues({ limit: 200 }).then((res) => {
-        useIssueStore.getState().setIssues(res.issues);
-      }).catch(console.error);
+      useIssueStore.getState().fetch().catch(console.error);
     } finally {
       setLoading(false);
       setDeleteOpen(false);