fix: steps/agenda desc text used sub1_color (near-invisible on slide)

The Steps minter's description and one Agenda template's item color bound
to sub1_color (#E7EAE7) — a near-white background tint — so the inserted
text was almost invisible and didn't match the dialog preview's #666.
Use a readable mid-gray (#666666) matching the preview.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JBHyvN2grYj27kTTRPYmBK

Author: htlin222

src/util/agenda_minter.js

@@ -135,7 +135,9 @@ function buildAgendaTemplates_() {
 	const accent =
 		(typeof accent_color !== "undefined" && accent_color) || "#f29424";
 	const text = (typeof text_color !== "undefined" && text_color) || "#000000";
-	const sub1 = (typeof sub1_color !== "undefined" && sub1_color) || "#666666";
+	// Readable mid-gray for subdued item text. NOT sub1_color — that's a
+	// near-white background tint (#E7EAE7) and would be almost invisible.
+	const sub1 = "#666666";
 	return [
 		{
 			id: "numbered",

src/util/steps_minter.js

@@ -27,8 +27,10 @@ function buildStepsTemplates_() {
 		(typeof accent_color !== "undefined" && accent_color) || "#f29424";
 	const text =
 		(typeof text_color !== "undefined" && text_color) || "#000000";
-	const sub =
-		(typeof sub1_color !== "undefined" && sub1_color) || "#666666";
+	// Description text must be a readable mid-gray (matches the dialog preview's
+	// #666). Do NOT use sub1_color — that's a near-white background tint
+	// (#E7EAE7) and renders almost invisible on a white slide.
+	const sub = "#666666";
 	return [
 		{
 			id: "main",