added cover page to manual + header/footer

gallery/readme_banner.typ

@@ -1,20 +1,5 @@
 #import "/src/lib.typ": *
 
-#let theme = sys.inputs.at("theme", default: "default")
-
-#set page(
-  width: auto,
-  height: auto,
-  margin: 1cm,
-  fill: if theme == "default" {white} else {none}
-)
-
-#set text(
-  size: 12pt,
-  font: "Source Sans 3",
-  fill: if theme == "dark" {white} else {black}
-)
-
 #let hex-abc = "0123456789abcdef"
 #let g = gradient.linear(
   red,
@@ -47,4 +32,21 @@
 #let txt = "Jumble"
 #let cipher = bytes-to-hex(sha1(txt))
 
-*sha1("#txt") =* #colorize-hex(cipher)
+#let banner = [*sha1("#txt") =* #colorize-hex(cipher)]
+
+#let theme = sys.inputs.at("theme", default: "default")
+
+#set page(
+  width: auto,
+  height: auto,
+  margin: 1cm,
+  fill: if theme == "default" {white} else {none}
+)
+
+#set text(
+  size: 12pt,
+  font: "Source Sans 3",
+  fill: if theme == "dark" {white} else {black}
+)
+
+#banner