feat(web): global word-wrap toggle for code and diff views (#985)

* refactor(web): add per-line shiki line-splitting helper

* feat(web): add global word-wrap toggle for code, markdown, and diff views

* feat(web): add a shaded gutter background behind line numbers

* fix(web): make DiffView compact rows follow the global wrap setting

web/src/lib/locales/en.ts

@@ -329,6 +329,8 @@ export default {
   // Code block
   'code.copy': 'Copy',
   'code.truncated': 'Preview truncated — open details for full output',
+  'code.wrap.enable': 'Enable word wrap',
+  'code.wrap.disable': 'Disable word wrap',
 
   // Diff view
   'diff.title': 'Diff',