feat: unified group management, public groups, and activity-based sidebar

Create Group wizard (Electron-only) consolidates 6 steps across 4 interfaces
into a single multi-step page: group creation on hub, node attachment, root
selection via folder picker, GEK initialization, and auto-pairing — all in one
flow. Browser SPA keeps its current behavior unchanged.

Public group support (Option A — GEK for all groups):
- All groups have GEK regardless of visibility; open-join groups auto-admit
  via TOFU when join_policy is "open"
- Key rotation blocked for public groups (API guard + UI hidden)
- Hub signaling allows WebRTC offers for nodes hosting open-join groups even
  when the caller isn't a member yet
- attach_group writes join_policy to node.toml
- Daemon loads GEK for all groups, not just private ones
- Known-device path in join_request now auto-admits to open-join groups

Node loopback API bridge (Electron IPC):
- node:detect, node:call, node:pairing-code IPC handlers in main process
- Renderer never sees tokens, paths, or keys (session token = physical access)
- platform.js node namespace for UI consumption
- Loopback endpoints: roots CRUD, member-upload toggle, reload

Bug fixes:
- Root change detection: removed premature ctx["roots"] updates from add_root
  and remove_root that prevented indexer retarget on reload
- Duplicate offline message: global fallback now gated on !group
- Signaling membership check: fallback to open-join groups for non-members

Sidebar groups sorted by last_activity_at (most recent first):
- New Group.last_activity_at column with Alembic migration
- POST /v1/groups/{id}/activity endpoint, called on connect and chat send
- Client-side sort + throttled hub updates (1/min)

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

1 files changed, 68 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/style.css b/packages/meshbay-hub/src/meshbay_hub/static/style.css
index ac3d08f..7ce073a 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/style.css
+++ b/packages/meshbay-hub/src/meshbay_hub/static/style.css
@@ -2222,3 +2222,71 @@ a.transfer-name {
   align-items: center;
 }
 .node-attach-dir-row input { flex: 1; }
+
+/* ── Create Group Wizard ──────────────────────────────────────────────────── */
+
+.wizard-root {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 8px 12px;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  gap: 8px;
+}
+.wizard-root + .wizard-root { margin-top: 6px; }
+.wizard-root-info {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  flex: 1;
+  min-width: 0;
+}
+.wizard-root-name { font-weight: 500; }
+.wizard-root-path {
+  font-size: 0.82em;
+  color: var(--text-dim);
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.wizard-root-actions {
+  display: flex;
+  gap: 4px;
+  flex-shrink: 0;
+}
+
+.wizard-progress {
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+  margin-top: 16px;
+}
+.wizard-step {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 10px 14px;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  font-size: 0.9em;
+}
+.wizard-step-icon {
+  width: 20px;
+  text-align: center;
+  font-weight: 600;
+}
+.wizard-step-done .wizard-step-icon { color: var(--success); }
+.wizard-step-running .wizard-step-icon { color: var(--accent); }
+.wizard-step-error .wizard-step-icon { color: var(--error); }
+.wizard-step-pending { opacity: 0.5; }
+
+.warning-msg {
+  padding: 10px 14px;
+  background: color-mix(in srgb, #f59e0b 15%, transparent);
+  border: 1px solid #f59e0b;
+  border-radius: 8px;
+  font-size: 0.85em;
+}