fix(sessions): show all sessions across all projects (closes #48) (#50)

* fix(sessions): load all sessions across projects, not just active directory

Closes #48

Root cause: loadSessions() used connState.client which carries the
active connection's directory as x-opencode-directory header. The server
filters sessions by that directory, so only the current project's sessions
were visible.

Fix: call clientForDirectory(undefined) to get a no-header client.
The server then returns sessions from all projects.

The session row UI already showed a directory badge (shortDir from
session.directory), so no UI change is needed — each session already
displays its project folder name.

* fix(sessions): preserve directory when opening rows

Carry each listed session directory into the route so selection, messages, and follow-up operations use the matching project client.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

app/(tabs)/index.tsx

@@ -49,7 +49,10 @@ function SessionItem({
   onDelete: () => void
 }) {
   const onPress = () => {
-    router.push(`/session/${session.id}`)
+    router.push({
+      pathname: `/session/[id]`,
+      params: { id: session.id, ...(session.directory ? { directory: session.directory } : {}) },
+    })
   }
 
   const onLongPress = () => {