Add energy tracker (/projects/energy)

Public, read-only page over the ned-collector energy schema: latest-hour
mix and per-source utilization, generation vs consumption with CO2
intensity (day/week/month/12 months/all years), NED forecast, gas storage
by year and per site, and gas-fired power share vs storage fill.
Incomplete hours (sources not summing to the NED total) are left out and
partial days/months/years are marked.

tests/energy.test.ts

@@ -0,0 +1,17 @@
+import { expect, test } from '@playwright/test';
+
+test('energy tracker renders its charts and is listed under trackers', async ({ page }) => {
+	await page.goto('/projects/energy');
+	await expect(page.getByRole('heading', { level: 1, name: 'Energy' })).toBeVisible();
+	await expect(page.getByRole('heading', { name: 'Generation and consumption' })).toBeVisible();
+	await expect(page.locator('canvas').first()).toBeVisible();
+	for (const range of ['day', 'month', '12 months', 'all years']) {
+		await page.getByRole('tab', { name: range, exact: true }).click();
+		await expect(page.getByRole('tab', { name: range, exact: true })).toHaveAttribute(
+			'data-state',
+			'active'
+		);
+	}
+	await page.goto('/trackers');
+	await expect(page.locator('a[href="/projects/energy"]').first()).toBeVisible();
+});