feat(search): sender picker, date presets, has:link filter

- Add SelectSenderButton: clickable people picker for the From filter
  replacing the text-only from:@user syntax
- Add date preset shortcuts in DateRangeButton (Today, Last week,
  Last month, Last year) for one-click range selection
- Add Has link chip backed by Matrix contains_url API filter; toggle
  removes cleanly with X badge
- Wire containsUrl through URL params, useMessageSearch hook, and
  SearchFilters props

UNTESTED — verify at chat.lotusguild.org post-deploy.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/features/message-search/MessageSearch.tsx

@@ -35,6 +35,7 @@ const useSearchPathSearchParams = (searchParams: URLSearchParams): _SearchPathSe
       senders: searchParams.get('senders') ?? undefined,
       fromTs: searchParams.get('fromTs') ?? undefined,
       toTs: searchParams.get('toTs') ?? undefined,
+      containsUrl: searchParams.get('containsUrl') ?? undefined,
     }),
     [searchParams],
   );
@@ -197,6 +198,7 @@ export function MessageSearch({
       senders: searchParamsSenders ?? senders,
       fromTs: searchPathSearchParams.fromTs ? Number(searchPathSearchParams.fromTs) : undefined,
       toTs: searchPathSearchParams.toTs ? Number(searchPathSearchParams.toTs) : undefined,
+      containsUrl: searchPathSearchParams.containsUrl === 'true' ? true : undefined,
     };
   }, [searchPathSearchParams, searchParamRooms, searchParamsSenders, rooms, senders]);
 
@@ -357,6 +359,18 @@ export function MessageSearch({
     [setSearchParams],
   );
 
+  const handleContainsUrlChange = useCallback(
+    (value?: boolean) => {
+      setSearchParams((prevParams) => {
+        const p = new URLSearchParams(prevParams);
+        p.delete('containsUrl');
+        if (value) p.append('containsUrl', 'true');
+        return p;
+      });
+    },
+    [setSearchParams],
+  );
+
   const lastVItem = vItems[vItems.length - 1];
   const lastVItemIndex: number | undefined = lastVItem?.index;
   const lastGroupIndex = groups.length - 1;
@@ -409,6 +423,8 @@ export function MessageSearch({
           fromTs={msgSearchParams.fromTs}
           toTs={msgSearchParams.toTs}
           onDateRangeChange={handleDateRangeChange}
+          containsUrl={msgSearchParams.containsUrl}
+          onContainsUrlChange={handleContainsUrlChange}
         />
       </Box>