fix(ui-ux): make analysis-run digest verification keyboard/touch accessible

frontend/src/App.css

@@ -327,6 +327,21 @@
   font-size: 0.85rem;
 }
 
+/* Reproducibility digest prefixes read inline in the '·'-separated post-meta line. */
+.analysis-run-digest {
+  display: inline;
+}
+
+.analysis-run-digest > summary {
+  display: inline;
+  cursor: pointer;
+  list-style: none;
+}
+
+.analysis-run-digest > summary::-webkit-details-marker {
+  display: none;
+}
+
 .visually-hidden {
   position: absolute;
   width: 1px;

frontend/src/App.test.tsx

@@ -2658,17 +2658,27 @@ describe("App, authenticated", () => {
     expect(screen.getByText(/Cutoff 2026-01-12/)).toBeInTheDocument();
     expect(screen.getByText(/Requested 2026-01-12/)).toBeInTheDocument();
     const digests = screen.getByLabelText("Analysis run reproducibility digests");
-    expect(digests).toHaveTextContent("Hover a prefix to read the full digest for verification.");
+    expect(digests).toHaveTextContent("Open a prefix to read the full digest for verification.");
     expect(digests).toHaveTextContent("Code abcdef012345");
     expect(digests).toHaveTextContent("Config 0123456789ab");
-    expect(digests).not.toHaveTextContent("abcdef0123456789deadbeefcafebabe");
-    expect(digests).not.toHaveTextContent(
+    // The disclosures are native <details>/<summary> -- no tabIndex/role/onClick hack --
+    // so they are keyboard- and touch-operable with zero JS, unlike a hover-only title tooltip.
+    const codeDisclosure = screen.getByText("Code abcdef012345").closest("details");
+    const configDisclosure = screen.getByText("Config 0123456789ab").closest("details");
+    expect(codeDisclosure).not.toHaveAttribute("open");
+    expect(configDisclosure).not.toHaveAttribute("open");
+    expect(screen.getByText("Code abcdef012345").tagName).toBe("SUMMARY");
+    expect(screen.getByText("Code abcdef012345")).not.toHaveAttribute("tabIndex");
+    expect(screen.getByText("Code abcdef012345")).not.toHaveAttribute("role");
+    await userEvent.click(screen.getByText("Code abcdef012345"));
+    expect(codeDisclosure).toHaveAttribute("open");
+    expect(codeDisclosure).toHaveTextContent("abcdef0123456789deadbeefcafebabe");
+    expect(configDisclosure).not.toHaveAttribute("open");
+    await userEvent.click(screen.getByText("Config 0123456789ab"));
+    expect(configDisclosure).toHaveAttribute("open");
+    expect(configDisclosure).toHaveTextContent(
       "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
     );
-    expect(screen.getByTitle("abcdef0123456789deadbeefcafebabe")).toHaveTextContent("Code abcdef012345");
-    expect(
-      screen.getByTitle("0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"),
-    ).toHaveTextContent("Config 0123456789ab");
     const history = screen.getByRole("list", { name: "Analysis run status history" });
     expect(history).toHaveTextContent("Pending 2026-01-12 12:31");
     expect(history).toHaveTextContent("Running 2026-01-12 12:32");
@@ -3305,7 +3315,11 @@ describe("App, authenticated", () => {
     );
     const digests = screen.getByLabelText("Analysis run reproducibility digests");
     expect(digests).toHaveTextContent("Result aaaaaaaaaaaa");
-    expect(screen.getByTitle("aa".repeat(32))).toHaveTextContent("Result aaaaaaaaaaaa");
+    const resultDisclosure = screen.getByText("Result aaaaaaaaaaaa").closest("details");
+    expect(resultDisclosure).not.toHaveAttribute("open");
+    await userEvent.click(screen.getByText("Result aaaaaaaaaaaa"));
+    expect(resultDisclosure).toHaveAttribute("open");
+    expect(resultDisclosure).toHaveTextContent("aa".repeat(32));
     const startCall = fetchMock.mock.calls.find((call) =>
       String(call[0]).endsWith("/api/analysis-runs/run-demo-lineage-pending/start"),
     );

frontend/src/App.tsx

@@ -2527,7 +2527,7 @@ function analysisRunCorpusHint(run: AnalysisRun): string | null {
   }
 }
 
-/** Git-style prefix. The full digest stays on `title` for verification. */
+/** Git-style prefix. The full digest is behind a `<details>` disclosure for verification. */
 const ANALYSIS_RUN_DIGEST_PREFIX_LENGTH = 12;
 
 function analysisRunDigestPrefix(digest: string): string {
@@ -2606,17 +2606,20 @@ function AnalysisRunReproducibilityDigests({
   }
   return (
     <div role="group" aria-label="Analysis run reproducibility digests">
-      <p className="post-meta">
+      <div className="post-meta">
         <span className="visually-hidden">
-          Hover a prefix to read the full digest for verification.{" "}
+          Open a prefix to read the full digest for verification.{" "}
         </span>
         {parts.map((part, index) => (
           <span key={part.label}>
             {index > 0 ? " · " : null}
-            <span title={part.digest}>{`${part.label} ${analysisRunDigestPrefix(part.digest)}`}</span>
+            <details className="analysis-run-digest">
+              <summary>{`${part.label} ${analysisRunDigestPrefix(part.digest)}`}</summary>
+              {part.digest}
+            </details>
           </span>
         ))}
-      </p>
+      </div>
     </div>
   );
 }