feat(web): click Executions' Started time to toggle relative/absolute

Both renderings are pre-rendered server-side into a <button>'s
data-relative/data-absolute attributes; app.js swaps textContent (and the
hover title, to the opposite value) on click, delegated on document.body
so it survives the card's own 5s htmx poll without needing to re-wire
after every swap. Click again to swap back.

docs/WEB-UI.md

@@ -359,6 +359,14 @@ table is wide as a result — 13 columns — and scrolls horizontally inside the
 card's own `.table-wrap` rather than the page, same as the other wide tables
 (Templates, Services).
 
+**Started is click-to-toggle.** It renders relative ("2h ago") by default;
+clicking swaps to the absolute local timestamp, and clicking again swaps
+back. Both strings are pre-rendered server-side into the button's
+`data-relative`/`data-absolute` attributes, so the swap (`app.js`, delegated
+on `document.body`) is instant and needs no request — and keeps working
+after the card's own 5s poll replaces the row, since the listener isn't on
+the button itself.
+
 Runs come from Gitea's Actions API: `/api/v1/admin/actions/runs` (every repo
 on the instance, admin token) with `/api/v1/user/actions/runs` as the
 non-admin fallback. Results are cached for 10s, so the card's 5s refresh costs

src/ci_orchestrator/web/static/app.css

@@ -501,6 +501,22 @@ input[type="text"], input[type="number"], select {
 /* Muted inline text (e.g. a relative-time suffix next to a file name). */
 .text-dim { color: var(--text-dim); }
 
+/* Executions "Started" cell: reset to read as plain inline text (no button
+ * chrome), with a dotted underline as the click-to-toggle affordance --
+ * not colour alone, same rule the rest of the app follows. app.js swaps
+ * between its data-relative/data-absolute values on click. */
+.time-toggle {
+  background: none;
+  border: none;
+  padding: 0;
+  margin: 0;
+  font: inherit;
+  cursor: pointer;
+  text-decoration: underline dotted;
+  text-underline-offset: 2px;
+}
+.time-toggle:hover { color: var(--text); }
+
 /* ── notices / confirm / result panels ───────────────────────────────── */
 
 .notice {

src/ci_orchestrator/web/static/app.js

@@ -204,6 +204,22 @@
     }
   });
 
+  // Executions "Started" cell: click swaps between the relative and
+  // absolute time already rendered into the button's own data attributes --
+  // no request. Delegated on body (not the button itself) so it keeps
+  // working after the Executions card's own 5s htmx poll replaces the row.
+  document.body.addEventListener("click", function (evt) {
+    var btn = evt.target.closest(".time-toggle");
+    if (!btn) {
+      return;
+    }
+    var next = btn.dataset.showing === "relative" ? "absolute" : "relative";
+    var shown = next === "relative" ? "absolute" : "relative";
+    btn.textContent = btn.dataset[next];
+    btn.title = btn.dataset[shown];
+    btn.dataset.showing = next;
+  });
+
   document.addEventListener("DOMContentLoaded", function () {
     observeStack();
     processSlot(document.getElementById("action-slot"));

src/ci_orchestrator/web/templates/partials/executions.html

@@ -89,7 +89,9 @@
           <td>{{ run.duration_sec | duration }}</td>
           <td>
             {% if run.started %}
-            <span class="text-dim" title="{{ run.started | localtime }}">{{ run.started | relative_time }}</span>
+            <button type="button" class="time-toggle text-dim" data-showing="relative"
+                    data-relative="{{ run.started | relative_time }}" data-absolute="{{ run.started | localtime }}"
+                    title="{{ run.started | localtime }}">{{ run.started | relative_time }}</button>
             {% else %}
             <span class="text-dim">—</span>
             {% endif %}
@@ -137,7 +139,9 @@
           <td><span class="text-dim">—</span></td>
           <td>
             {% if parsed.started %}
-            <span class="text-dim" title="{{ parsed.started | localtime }}">{{ parsed.started | relative_time }}</span>
+            <button type="button" class="time-toggle text-dim" data-showing="relative"
+                    data-relative="{{ parsed.started | relative_time }}" data-absolute="{{ parsed.started | localtime }}"
+                    title="{{ parsed.started | localtime }}">{{ parsed.started | relative_time }}</button>
             {% else %}
             <span class="text-dim">—</span>
             {% endif %}

tests/python/test_web_executions.py

@@ -340,6 +340,34 @@ def test_status_badge_has_no_icon_for_non_terminal_states(
     assert "#i-x" not in resp.text
 
 
+def test_started_cell_is_a_click_to_toggle_button(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Both the relative and absolute renderings are pre-rendered into the
+    button's data attributes -- app.js swaps textContent/title on click, no
+    round trip. Server-side, this test can only pin the markup the toggle
+    depends on, not the click itself."""
+    _stub_view(
+        monkeypatch,
+        ExecutionsView(
+            runs=[_execution(started="2026-07-25T11:50:00Z")],
+            unmatched_vms=[],
+            source="admin",
+            error=None,
+        ),
+    )
+    app = create_app(_make_config(tmp_path))
+    app.dependency_overrides[get_backend] = lambda: _FakeBackend([])
+    client = TestClient(app)
+
+    resp = client.get("/executions")
+
+    assert '<button type="button" class="time-toggle text-dim"' in resp.text
+    assert 'data-showing="relative"' in resp.text
+    assert 'data-relative="' in resp.text
+    assert 'data-absolute="' in resp.text
+
+
 def test_no_cell_stacks_two_facts_on_separate_lines(
     tmp_path: Path, monkeypatch: pytest.MonkeyPatch
 ) -> None: