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/insights/__tests__/metric-target-summary.test.tsx

@@ -161,7 +161,13 @@ describe("<MetricTargetSummary>", () => {
     // redundant "Target: 60.1–80.9 kg" string above it.
     expect(html).toContain('data-slot="tile-header"');
     expect(html).toContain("Target");
-    expect(html).not.toContain("Target: 60.1–80.9 kg");
+    // 2026-07-17 a11y audit (M1) — the range-bar marker now carries an
+    // `aria-label` that reuses this same string as a text alternative
+    // (screen-reader only, not a rendered heading) — strip attribute
+    // values before asserting no redundant VISIBLE "Target: …" text node
+    // exists above the bar.
+    const visibleText = html.replace(/aria-label="[^"]*"/g, "");
+    expect(visibleText).not.toContain("Target: 60.1–80.9 kg");
     // The min / max endpoints surface as the range-bar axis labels.
     expect(html).toContain("60.1 kg");
     expect(html).toContain("80.9 kg");