Fix automatic readable text contrast for public and admin themes.

Derive admin/public text colors from WCAG contrast, unify ThemeVars CSS emission, and keep navbar overrides in sync with readable vars.

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

src/lib/theme-contrast.test.ts

@@ -130,6 +130,48 @@ describe("deriveAdminPalette", () => {
 		expect(admin.canvas).not.toBe("#ff00ff");
 		expect(admin.surface).not.toBe("#00ff00");
 	});
+
+	it("repairs default light text when admin canvas is forced light", () => {
+		const admin = deriveAdminPalette(
+			{ color_primary: "#f59e0b" },
+			{
+				canvas: "#ffffff",
+				surface: "#f8fafc",
+				surfaceElevated: "#f1f5f9",
+				sidebar: "#ffffff",
+			},
+		);
+		expect(contrastRatio(admin.text, admin.canvas)).toBeGreaterThanOrEqual(4.5);
+		expect(contrastRatio(admin.text, admin.surface)).toBeGreaterThanOrEqual(4.5);
+		expect(contrastRatio(admin.muted, admin.surface)).toBeGreaterThanOrEqual(
+			4.5,
+		);
+		expect(
+			contrastRatio(admin.sidebarText, admin.sidebar),
+		).toBeGreaterThanOrEqual(4.5);
+		expect(
+			contrastRatio(admin.accentForeground, admin.accent),
+		).toBeGreaterThanOrEqual(4.5);
+	});
+
+	it("repairs hostile admin text overrides on dark canvas", () => {
+		const admin = deriveAdminPalette(
+			{ color_primary: "#111827" },
+			{
+				canvas: "#0b0f19",
+				surface: "#151b27",
+				text: "#0b0f19",
+				muted: "#111827",
+			},
+		);
+		expect(contrastRatio(admin.text, admin.canvas)).toBeGreaterThanOrEqual(4.5);
+		expect(contrastRatio(admin.muted, admin.surface)).toBeGreaterThanOrEqual(
+			4.5,
+		);
+		expect(
+			contrastRatio(admin.accentForeground, admin.accent),
+		).toBeGreaterThanOrEqual(4.5);
+	});
 });
 
 describe("derivePublicForegrounds", () => {