fix(a11y): keyboard-reachable admin log rows, range-bar marker, heatmap cells

Admin app-log rows opened their JSON detail dialog through a click-only
<tr> with no keyboard path; the Action cell now wraps a real <button>
that carries the same handler plus a descriptive aria-label, leaving
the row onClick as a pointer convenience.

The target range-bar's current-value marker showed value + band only
in a hover-only tooltip on a non-focusable div. It is now focusable
(tabIndex, role=img) with an aria-label that reuses the same value /
range / delta copy the tooltip already renders, so focus opens the
tooltip and a screen reader gets the text alternative either way.

Mood and medication-compliance heatmap day cells were pointer-only SVG
rects. Each cell is now focusable with its own per-day aria-label
(reusing the existing tooltip copy), and Escape dismisses any open
tooltip — pinned (touch) or focus-shown.

Reference: 2026-07-17 a11y audit, H1 + M1 + M2.

src/components/admin/__tests__/app-log-preview-summary-position.test.tsx

@@ -98,3 +98,16 @@ describe("AppLogPreviewSection — summary lives outside the scroll wrapper", ()
     expect(wrapper![0]).not.toContain("app-log-preview-summary");
   });
 });
+
+describe("AppLogPreviewSection — row detail is keyboard-reachable (2026-07-17 a11y audit H1)", () => {
+  // The row itself stays a pointer-only convenience (`onClick` on the
+  // `<tr>`); a real `<button>` in the Action cell gives keyboard / switch
+  // users a focusable, activatable path to the same detail dialog.
+  it("renders a real button carrying the action label and a descriptive aria-label", () => {
+    const html = render();
+    expect(html).toMatch(
+      /<button[^>]*type="button"[^>]*>auth\.login\.success</,
+    );
+    expect(html).toContain('aria-label="View details for auth.login.success');
+  });
+});