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/i18n/en.ts

@@ -745,7 +745,7 @@ export const en: Record<string, string> = {
   "ops.newMeeting": "New meeting",
   "ops.newSprint": "New sprint",
   "ops.deleteDocument": "Delete document",
-  "ops.deleteDocumentMsg": "This removes the document from the company knowledge surface.",
+  "ops.deleteDocumentMsg": "This removes the document from the company knowledge bg-card border border-border shadow-sm.",
   "ops.deleteKnowledgeEntry": "Delete knowledge entry",
   "ops.deleteKnowledgeMsg": "This removes the entry from the shared company knowledge base.",
   "ops.deleteMeeting": "Delete meeting",