activity, capabilities, chat history and the locale picker (21 -> 2)

The locale picker's labels are now AUTONYMS computed from Intl -- each language named
in its own language, so "Português europeu" reads as Portuguese whichever locale the
UI is in. That is the convention for a language picker and the useful behaviour:
somebody who cannot read the current language still has to find theirs.

CapabilityPage interpolated the capability KIND into six strings by lowercasing it in
code. "skill" does not lowercase into a Portuguese noun, so kind is a parameter now.

What is left is two strings, both deliberate: see the next commit message.

src/apps/officer-web/Screens/Dashboard/CapabilityPage.tsx

@@ -12,6 +12,7 @@ import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogDescription } f
 import { useClient } from 'hooks/useClient';
 import { Card } from '@/components/Card';
 import { useChat, EmbeddableChat } from 'officerdev';
+import { useTranslation } from '@/lib/i18n';
 type CapabilitySummary = {
   dirName: string;
   name: string;
@@ -301,6 +302,7 @@ export const CapabilityChat = ({
 };
 
 export const FrontmatterBlock = ({ yaml }: { yaml: string }) => {
+  const { t } = useTranslation();
   const [open, setOpen] = useState(false);
 
   return (
@@ -310,7 +312,7 @@ export const FrontmatterBlock = ({ yaml }: { yaml: string }) => {
         className="flex w-full items-center gap-1.5 px-3 py-1.5 text-duck-dark/50 hover:text-duck-dark/70 cursor-pointer transition-colors"
       >
         <ChevronRight className={`h-3.5 w-3.5 transition-transform ${open ? 'rotate-90' : ''}`} />
-        <span className="text-xs font-medium">Frontmatter</span>
+        <span className="text-xs font-medium">{t('capability.frontmatter')}</span>
       </button>
       {open && (
         <pre className="px-4 pb-3 text-xs text-duck-dark/60 whitespace-pre-wrap font-mono leading-relaxed">{yaml}</pre>
@@ -330,6 +332,7 @@ export const CapabilityList = ({
   showCreate,
   onShowCreateChange,
 }: CapabilityListProps) => {
+  const { t, tUi } = useTranslation();
   const client = useClient();
   const qc = useQueryClient();
   const [internalCreating, setInternalCreating] = useState(false);
@@ -356,7 +359,7 @@ export const CapabilityList = ({
       setNewName('');
       onCreate(res.dirName);
     } catch {
-      toast.error(`Failed to create ${kind}`);
+      toast.error(t('capability.createFailed', { kind: kind.toLowerCase() }));
     }
   };
 
@@ -427,7 +430,7 @@ export const CapabilityList = ({
             <input
               value={internalSearch}
               onChange={(ev) => setInternalSearch(ev.target.value)}
-              placeholder={`Search ${kind.toLowerCase()}s...`}
+              placeholder={t('capability.searchPlaceholder', { kind: `${kind.toLowerCase()}s` })}
               className="w-full rounded border border-duck-dark/15 bg-background/80 pl-7 pr-2 py-1 text-base md:text-sm text-duck-dark placeholder:text-duck-dark/30 focus:outline-none focus:ring-1 focus:ring-duck-teal/30"
             />
           </div>
@@ -452,7 +455,7 @@ export const CapabilityList = ({
           <p className="text-sm text-duck-dark/40 px-4 py-6 text-center">No {kind.toLowerCase()}s found</p>
         )}
         {items.length > 0 && filtered.length === 0 && (
-          <p className="text-sm text-duck-dark/40 px-4 py-6 text-center">No matches</p>
+          <p className="text-sm text-duck-dark/40 px-4 py-6 text-center">{t('capability.noMatches')}</p>
         )}
       </div>
     </>
@@ -469,6 +472,7 @@ export const CapabilityList = ({
  * them for free — no reset effect racing the navigation. `edit` also makes the editor pane linkable.
  */
 export const CapabilityPage = ({ kind, endpoint, queryKey, basePath }: CapabilityPageProps) => {
+  const { t, tUi } = useTranslation();
   const client = useClient();
   const qc = useQueryClient();
   const navigate = useNavigate();
@@ -497,7 +501,7 @@ export const CapabilityPage = ({ kind, endpoint, queryKey, basePath }: Capabilit
       navigate(basePath, { replace: true });
       await qc.invalidateQueries({ queryKey: [queryKey] });
     } catch {
-      toast.error(`Failed to delete ${kind}`);
+      toast.error(t('capability.deleteFailed', { kind: kind.toLowerCase() }));
     }
   };
 
@@ -526,7 +530,7 @@ export const CapabilityPage = ({ kind, endpoint, queryKey, basePath }: Capabilit
                 <ArrowLeft className="h-4 w-4 text-duck-dark/60" />
               </Link>
               <span className="text-sm font-medium text-duck-dark/70 flex-1">
-                {detail?.name ?? `Select a ${kind.toLowerCase()}`}
+                {detail?.name ?? t('capability.selectOne', { kind: kind.toLowerCase() })}
               </span>
               {detail && (
                 <>
@@ -554,10 +558,10 @@ export const CapabilityPage = ({ kind, endpoint, queryKey, basePath }: Capabilit
                   </ReactMarkdown>
                 </article>
               ) : detail ? (
-                <p className="text-sm text-duck-dark/40 text-center mt-12">Empty file</p>
+                <p className="text-sm text-duck-dark/40 text-center mt-12">{t('capability.emptyFile')}</p>
               ) : (
                 <p className="text-sm text-duck-dark/40 text-center mt-12">
-                  Select a {kind.toLowerCase()} to view its contents
+                  {t('capability.selectToView', { kind: kind.toLowerCase() })}
                 </p>
               )}
             </div>
@@ -606,10 +610,10 @@ export const CapabilityPage = ({ kind, endpoint, queryKey, basePath }: Capabilit
           </DialogHeader>
           <div className="flex justify-end gap-2 mt-2">
             <Button variant="outline" onClick={() => setDeleteConfirm(false)} className="cursor-pointer">
-              Cancel
+              {tUi('button.cancel')}
             </Button>
             <Button variant="destructive" onClick={handleDelete} className="cursor-pointer">
-              Delete
+              {t('capability.delete')}
             </Button>
           </div>
         </DialogContent>