style(scaffolds/manual): align vertical rhythm with Typst md-to-pdf/manual template

- Add setspace and set \setstretch{1.2} to match Typst leading 0.76em
  (baseline-to-baseline ~1.46em for 10pt text).
- Set \parindent=0pt and \parskip=0.6em so paragraph breaks match
  Typst paragraph spacing 1.08em.
- Replace nosep lists with itemsep=0.2em / topsep=0.4em to match
  Typst list spacing 0.72em.
- Add aboveskip/belowskip=0.8em around code listings for consistent
  block separation.

mytoolkit/scaffolds/manual/main.tex

@@ -14,6 +14,7 @@
 \usepackage{titlesec}
 \usepackage{fancyhdr}
 \usepackage{enumitem}
+\usepackage{setspace}
 \usepackage{hyperref}
 
 % ---- fonts (Times New Roman + SimSun/SimHei/KaiTi; ctex default set as fallback) ----
@@ -24,6 +25,14 @@
 }{}
 \IfFontExistsTF{Courier New}{\setmonofont{Courier New}}{\setmonofont{Menlo}}
 
+% ---- vertical rhythm (keep in sync with Typst md-to-pdf/manual template) ----
+% Typst: leading 0.76em, paragraph spacing 1.08em
+% LaTeX uses baseline-to-baseline; 1.2 stretch gives ~1.46em baseline,
+% close to Typst leading + cap-height.  Parskip adds the remaining gap.
+\setstretch{1.2}
+\setlength{\parindent}{0pt}
+\setlength{\parskip}{0.6em}
+
 % ---- palette (keep in sync with templates/md-to-pdf/manual/template.typ) ----
 \definecolor{primary}{HTML}{1F4E79}
 \definecolor{secondary}{HTML}{2C3E50}
@@ -63,8 +72,8 @@
 \fancyhead[R]{\fontsize{8}{10}\selectfont\color{light}\rightmark}
 \fancyfoot[C]{\fontsize{8}{10}\selectfont\color{light}--- \thepage\ ---}
 
-% ---- compact lists ----
-\setlist{nosep, leftmargin=1.8em}
+% ---- list spacing (Typst list spacing 0.72em -> itemsep 0.2em on top of line gap) ----
+\setlist{leftmargin=1.8em, itemsep=0.2em, parsep=0pt, topsep=0.4em}
 
 % ---- three-line tables: \toprule / \midrule / \bottomrule ----
 \arrayrulecolor{ruleblue}
@@ -75,6 +84,7 @@
     backgroundcolor=\color{codebg},
     frame=single, framerule=0.5pt, rulecolor=\color{ruleblue},
     framesep=3pt, xleftmargin=2em,
+    aboveskip=0.8em, belowskip=0.8em,
     numbers=left, numberstyle=\tiny\color{codenum}, numbersep=8pt,
     breaklines=true, columns=fullflexible, keepspaces=true,
     showstringspaces=false,