feat(11-02): replace 1113 old CSS variable references with Paperclip design tokens

- Replace all bg-[color:var(--old)] with bg-background/bg-card/bg-muted/bg-primary etc.
- Replace all text-[color:var(--old)] with text-foreground/text-muted-foreground/text-primary etc.
- Replace all border-[color:var(--line)] with border-border
- Replace all inline var(--old) with var(--new) equivalents
- Replace all rounded-[6px]/rounded-[8px] with rounded-lg
- Replace .surface class with bg-card border border-border shadow-sm
- Replace .focus-ring class with focus-visible Tailwind utilities
- Replace .mono class with font-mono
- Replace data-theme attribute with class-based dark mode
- 99 files updated, ~1265 lines changed, zero old references remaining

src/renderer/components/company-operations/SectionHeader.tsx

@@ -13,8 +13,8 @@ export function SectionHeader({
   return (
     <div className="mb-4 flex items-center justify-between">
       <div>
-        <div className="text-[16px] font-semibold text-[color:var(--text)]">{title}</div>
-        <div className="text-[12px] text-[color:var(--muted)]">{count} item{count === 1 ? "" : "s"}</div>
+        <div className="text-[16px] font-semibold text-foreground">{title}</div>
+        <div className="text-[12px] text-muted-foreground">{count} item{count === 1 ? "" : "s"}</div>
       </div>
       <ActionButton label="New" icon={Plus} tone="accent" onClick={action} />
     </div>