Fix theme switcher desync and auto-correct unreadable saved colors.

Sync dark-mode state from the DOM after mount so admin text no longer needs a double toggle, and normalize text/button colors against their surfaces on theme save.

Co-authored-by: Cursor <[email protected]>

src/lib/theme-contrast.test.ts

@@ -174,6 +174,38 @@ describe("deriveAdminPalette", () => {
 	});
 });
 
+describe("ensureReadableThemeColors", () => {
+	it("rewrites saved text colors that fail against their surfaces", async () => {
+		const { ensureReadableThemeColors } = await import("@/lib/theme-contrast");
+		const fixed = ensureReadableThemeColors({
+			color_background: "#0b0f19",
+			color_surface: "#151b27",
+			color_text: "#0b0f19",
+			color_text_muted: "#111827",
+			color_navbar: "#ffffff",
+			color_navbar_text: "#ffffff",
+			button_primary_color: "#f59e0b",
+			button_text_color: "#f59e0b",
+			admin_canvas: "#ffffff",
+			admin_surface: "#f8fafc",
+			admin_text: "#f8fafc",
+			admin_text_muted: "#e2e8f0",
+		});
+		expect(
+			contrastRatio(fixed.color_text, fixed.color_surface),
+		).toBeGreaterThanOrEqual(4.5);
+		expect(
+			contrastRatio(fixed.color_navbar_text, fixed.color_navbar),
+		).toBeGreaterThanOrEqual(4.5);
+		expect(
+			contrastRatio(fixed.button_text_color, fixed.button_primary_color),
+		).toBeGreaterThanOrEqual(4.5);
+		expect(
+			contrastRatio(fixed.admin_text, fixed.admin_canvas),
+		).toBeGreaterThanOrEqual(4.5);
+	});
+});
+
 describe("derivePublicForegrounds", () => {
 	it.each(
 		Object.entries(PRESETS),