feat: Afficher la couleur des matières dans l'emploi du temps élève et parent

L'admin pouvait attribuer une couleur à chaque matière, mais cette
couleur n'était utilisée que dans la vue admin de l'emploi du temps.
Les APIs élève et parent ne renvoyaient pas cette information, ce qui
donnait un affichage générique (gris/bleu) pour tous les créneaux.

L'API renvoie désormais subjectColor dans chaque créneau, et les vues
jour/semaine/widget/détails affichent la bordure colorée correspondante.
Le marqueur "Prochain cours" conserve sa priorité visuelle via une
surcharge CSS variable.

frontend/e2e/child-selector.spec.ts

@@ -147,11 +147,11 @@ test.describe('Child Selector', () => {
 		// Should display the label
 		await expect(childSelector.locator('.child-selector-label')).toHaveText('Enfant :');
 
-		// Should have 2 child buttons
+		// Should have 3 buttons: "Tous" + 2 children
 		const buttons = childSelector.locator('.child-button');
-		await expect(buttons).toHaveCount(2);
+		await expect(buttons).toHaveCount(3);
 
-		// First child should be auto-selected
+		// "Tous" button should be selected initially (no child auto-selected)
 		await expect(buttons.first()).toHaveClass(/selected/);
 	});
 
@@ -162,18 +162,18 @@ test.describe('Child Selector', () => {
 		await expect(childSelector).toBeVisible({ timeout: 10000 });
 
 		const buttons = childSelector.locator('.child-button');
-		await expect(buttons).toHaveCount(2);
+		await expect(buttons).toHaveCount(3);
 
-		// First button should be selected initially
-		await expect(buttons.first()).toHaveClass(/selected/);
+		// "Tous" button (index 0) should be selected initially
+		await expect(buttons.nth(0)).toHaveClass(/selected/);
 		await expect(buttons.nth(1)).not.toHaveClass(/selected/);
 
-		// Click second button
+		// Click first child button (index 1)
 		await buttons.nth(1).click();
 
-		// Second button should now be selected, first should not
+		// First child should now be selected, "Tous" should not
 		await expect(buttons.nth(1)).toHaveClass(/selected/);
-		await expect(buttons.first()).not.toHaveClass(/selected/);
+		await expect(buttons.nth(0)).not.toHaveClass(/selected/);
 	});
 
 	test('[P1] parent with single child should see static child name', async ({ browser, page }) => {

frontend/e2e/parent-schedule.spec.ts

@@ -114,6 +114,21 @@ async function loginAsParent(page: import('@playwright/test').Page) {
 	]);
 }
 
+/**
+ * Multi-child parents land on the summary view (no child auto-selected).
+ * This helper selects the first actual child (skipping the "Tous" button).
+ */
+async function selectFirstChild(page: import('@playwright/test').Page) {
+	const childButtons = page.locator('.child-button');
+	await expect(childButtons.first()).toBeVisible({ timeout: 15000 });
+	const count = await childButtons.count();
+	if (count > 2) {
+		// Multi-child: "Tous" is at index 0, first child at index 1
+		await childButtons.nth(1).click();
+	}
+	// Single child is auto-selected, nothing to do
+}
+
 test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 	test.describe.configure({ mode: 'serial' });
 
@@ -305,6 +320,7 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 			await expect(
 				page.getByRole('heading', { name: /emploi du temps des enfants/i })
 			).toBeVisible({ timeout: 15000 });
+			await selectFirstChild(page);
 			await navigateToSeededDay(page);
 
 			// Wait for slots to load
@@ -324,19 +340,29 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 				page.getByRole('heading', { name: /emploi du temps des enfants/i })
 			).toBeVisible({ timeout: 15000 });
 
-			// If multiple children, buttons should be visible
+			// Multi-child: "Tous" + N children buttons
 			const childButtons = page.locator('.child-button');
 			const count = await childButtons.count();
 
-			if (count > 1) {
-				// Click second child
+			if (count > 2) {
+				// Select first child (index 1, after "Tous")
 				await childButtons.nth(1).click();
-				await page.waitForTimeout(500);
-
-				// Should update schedule data
 				await navigateToSeededDay(page);
-				const slots = page.locator('[data-testid="schedule-slot"]');
-				await expect(slots.first()).toBeVisible({ timeout: 20000 });
+				await expect(page.locator('[data-testid="schedule-slot"]').first()).toBeVisible({
+					timeout: 20000
+				});
+
+				// Switch to second child (index 2)
+				await childButtons.nth(2).click();
+				await page.waitForTimeout(500);
+				await navigateToSeededDay(page);
+				await expect(page.locator('[data-testid="schedule-slot"]').first()).toBeVisible({
+					timeout: 20000
+				});
+
+				// Switch back to "Tous" summary view
+				await childButtons.nth(0).click();
+				await expect(page.locator('.multi-child-summary')).toBeVisible({ timeout: 10000 });
 			}
 		});
 	});
@@ -351,6 +377,7 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 			await expect(
 				page.getByRole('heading', { name: /emploi du temps des enfants/i })
 			).toBeVisible({ timeout: 15000 });
+			await selectFirstChild(page);
 
 			const dayButton = page.locator('.view-toggle button', { hasText: 'Jour' });
 			await expect(dayButton).toHaveClass(/active/, { timeout: 5000 });
@@ -362,6 +389,7 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 			await expect(
 				page.getByRole('heading', { name: /emploi du temps des enfants/i })
 			).toBeVisible({ timeout: 15000 });
+			await selectFirstChild(page);
 			await navigateToSeededDay(page);
 
 			// Wait for slots to load
@@ -384,6 +412,7 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 			await expect(
 				page.getByRole('heading', { name: /emploi du temps des enfants/i })
 			).toBeVisible({ timeout: 15000 });
+			await selectFirstChild(page);
 			await navigateToSeededDay(page);
 
 			await expect(page.locator('[data-testid="schedule-slot"]').first()).toBeVisible({
@@ -419,6 +448,7 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 			await expect(
 				page.getByRole('heading', { name: /emploi du temps des enfants/i })
 			).toBeVisible({ timeout: 15000 });
+			await selectFirstChild(page);
 
 			// Wait for schedule slots to load
 			await expect(page.locator('[data-testid="schedule-slot"]').first()).toBeVisible({
@@ -448,9 +478,11 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 
 			const childButtons = page.locator('.child-button');
 			const count = await childButtons.count();
-			test.skip(count < 2, 'Need at least 2 children for this test');
+			// "Tous" + at least 2 children = 3 buttons minimum
+			test.skip(count < 3, 'Need at least 2 children for this test');
 
-			// Navigate to seeded day to see slots
+			// Select first child (index 1, after "Tous")
+			await childButtons.nth(1).click();
 			await navigateToSeededDay(page);
 
 			// First child (6A) should show Maths
@@ -461,8 +493,8 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 				timeout: 5000
 			});
 
-			// Switch to second child (5B) — should show SVT
-			await childButtons.nth(1).click();
+			// Switch to second child (index 2) (5B) — should show SVT
+			await childButtons.nth(2).click();
 			await navigateToSeededDay(page);
 			await expect(page.locator('[data-testid="schedule-slot"]').first()).toBeVisible({
 				timeout: 20000
@@ -480,6 +512,7 @@ test.describe('Parent Schedule Consultation (Story 4.4)', () => {
 		test('shows offline banner when network is lost', async ({ page, context }) => {
 			await loginAsParent(page);
 			await page.goto(`${ALPHA_URL}/dashboard/parent-schedule`);
+			await selectFirstChild(page);
 			await navigateToSeededDay(page);
 
 			// Wait for schedule to load