Address artifact grouping review feedback

ui/src/components/artifacts/ArtifactGroupCard.test.tsx

@@ -14,7 +14,7 @@ vi.mock("@/context/CompanyContext", () => ({
 function sampleArtifact(overrides: Partial<CompanyArtifact> = {}): CompanyArtifact {
   return {
     id: "artifact-1",
-    source: "image",
+    source: "attachment",
     mediaKind: "image",
     title: "Hero shot",
     previewText: null,

ui/src/pages/Artifacts.test.tsx

@@ -360,6 +360,7 @@ describe("Artifacts page", () => {
       expect(card).not.toBeNull();
       expect(card.getAttribute("data-count")).toBe("4");
       expect(card.getAttribute("data-stacked")).toBe("true");
+      expect(card.getAttribute("href")).toBe("/artifacts?groupIssueId=issue-1");
       expect(card.textContent).toContain("4 artifacts");
     });
 
@@ -389,6 +390,9 @@ describe("Artifacts page", () => {
         cursor: undefined,
       });
       expect(container.querySelector('[data-testid="artifact-stack-back"]')).not.toBeNull();
+      expect(
+        (container.querySelector('[data-testid="artifact-stack-back"]') as HTMLAnchorElement).getAttribute("href"),
+      ).toBe("/artifacts");
       expect(container.textContent).toContain("Stacked Artifact");
       expect(container.querySelector('[data-testid="artifact-card"]')).not.toBeNull();
     });

ui/src/pages/Artifacts.tsx

@@ -152,15 +152,20 @@ export function Artifacts() {
   const stackTo = useCallback(
     (issueId: string): To =>
       buildTo((next) => {
-        if (groupBy !== "none") next.set("groupBy", groupBy);
+        if (groupBy === "task") next.delete("groupBy");
+        else if (groupBy !== "none") next.set("groupBy", groupBy);
         next.set("groupIssueId", issueId);
       }),
     [buildTo, groupBy],
   );
 
   const backToStacksTo = useMemo<To>(
-    () => buildTo((next) => next.delete("groupIssueId")),
-    [buildTo],
+    () =>
+      buildTo((next) => {
+        if (groupBy === "task") next.delete("groupBy");
+        next.delete("groupIssueId");
+      }),
+    [buildTo, groupBy],
   );
 
   const {