feat: open a group, a folder or a file from a #/name@owner link

A group can now be reached by the handle shown under its name, and a path
after it points inside the group: #/name@owner/root/dir/file downloads the
file and opens Files on its folder; a folder opens Files there. The handle
is resolved in the client against the account's own /v1/groups/mine, so no
hub route answers for a name and nobody can probe for one. While a group is
open the address shows the handle (replace, no history entry); a linked path
is taken out of the address once acted on, so a reload does not download
twice.

Signing in no longer sends everyone home: the form stood in for the page the
address named, and that is where a link opened signed out was going.

group-link.js holds the parsing and lookups, executed whole by
test_group_link.py; harness/group_link_probe.py drives the router in Chrome.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/files-app.js b/packages/meshbay-hub/src/meshbay_hub/static/files-app.js
index 38157b9..978090c 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/files-app.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/files-app.js
@@ -142,12 +142,16 @@ function FilesPanel({
   entries, nodeDirs, nodeRoots, setEntries, setNodeDirs, setNodeRoots, applyIndex,
   isNodeAdmin, operatorPaired, userId, setError, onPreview,
   showGroup, readOnly, getTransport, onRefreshIndex, showRefresh, onReport,
+  openDirectory,
 }) {
   const [selected, setSelected] = useState(() => new Set());
   const [sortKey, setSortKey] = useState('name');
   const [sortAsc, setSortAsc] = useState(true);
   const [filter, setFilter] = useState('');
-  const [currentPath, setCurrentPath] = useState('');
+  const [currentPath, setCurrentPath] = useState(() => (openDirectory ? openDirectory.dir : ''));
+  // A link into the group named a folder (group-page.js); a new object each
+  // time, so the same folder linked twice is opened twice.
+  useEffect(() => { if (openDirectory) setCurrentPath(openDirectory.dir); }, [openDirectory]);
   const [refreshing, setRefreshing] = useState(false);
   // The toolbar pins below the page's own band and tells the column heads how
   // far down to pin. Its height is not a constant — it wraps to three rows on