feat(web): session-row Rename menu action with a browser-owned dialog

The row menu's Rename item opens the same dialog pattern as workspace rename
(no client-side conflict rule; the host normalizes) and resolves through the
session face via ctx.sessions.binding. Assembled-app snapshot covers the
row-menu -> dialog -> unary-settle flow.

apps/web/tests/snapshots/session-actions/rename-rows.json

@@ -0,0 +1,14 @@
+[
+  {
+    "label": "fixture4 sessions"
+  },
+  {
+    "label": "New Sessionnow"
+  },
+  {
+    "label": "分叉 实验记录now"
+  },
+  {
+    "label": "fixture2min"
+  }
+]