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, 66 insertions, 1 deletions

diff --git a/packages/meshbay-node/tests/test_roots.py b/packages/meshbay-node/tests/test_roots.py
index ea4ba6a..fc5bd64 100644
--- a/packages/meshbay-node/tests/test_roots.py
+++ b/packages/meshbay-node/tests/test_roots.py
@@ -11,7 +11,10 @@ from pathlib import Path
 
 import pytest
 
-from meshbay_node.roots import Root, RootError, RootSet, entry_abs_path
+from meshbay_node.roots import (
+    Root, RootError, RootSet, entry_abs_path,
+    SAFE_UPLOAD_NAME, safe_subdir, _free_name,
+)
 from meshbay_common.protocol import IndexEntry
 
 
@@ -240,3 +243,65 @@ def test_describe_reports_what_a_member_needs(tmp_path):
     # Deliberately no paths: a member is told what exists and whether it is
     # readable, not where on the operator's disk it lives.
     assert not any("path" in d for d in described)
+
+
+# ── SAFE_UPLOAD_NAME ────────────────────────────────────────────────────────
+
+def test_safe_name_accepts_unicode_letters():
+    assert SAFE_UPLOAD_NAME.match("rapport (1).pdf")
+    assert SAFE_UPLOAD_NAME.match("hello.txt")
+
+
+def test_safe_name_rejects_dotfiles():
+    assert not SAFE_UPLOAD_NAME.match(".hidden")
+    assert not SAFE_UPLOAD_NAME.match("..secret")
+
+
+def test_safe_name_rejects_trailing_dot_or_space():
+    assert not SAFE_UPLOAD_NAME.match("file.")
+    assert not SAFE_UPLOAD_NAME.match("file ")
+
+
+# ── _free_name ──────────────────────────────────────────────────────────────
+
+def test_free_name_returns_original_when_not_taken(tmp_path):
+    assert _free_name(tmp_path, "photo.jpg") == "photo.jpg"
+
+
+def test_free_name_appends_counter_on_collision(tmp_path):
+    (tmp_path / "photo.jpg").write_text("x")
+    assert _free_name(tmp_path, "photo.jpg") == "photo (2).jpg"
+
+
+def test_free_name_increments_past_multiple_collisions(tmp_path):
+    (tmp_path / "photo.jpg").write_text("x")
+    (tmp_path / "photo (2).jpg").write_text("x")
+    assert _free_name(tmp_path, "photo.jpg") == "photo (3).jpg"
+
+
+# ── safe_subdir ─────────────────────────────────────────────────────────────
+
+def test_safe_subdir_resolves_valid_path(tmp_path):
+    (tmp_path / "Films").mkdir()
+    (tmp_path / "Films" / "2024").mkdir()
+    roots = RootSet.build([_spec(tmp_path / "Films")])
+    assert safe_subdir(roots, "Films/2024") == (tmp_path / "Films" / "2024").resolve()
+
+
+def test_safe_subdir_refuses_traversal(tmp_path):
+    (tmp_path / "Films").mkdir()
+    roots = RootSet.build([_spec(tmp_path / "Films")])
+    assert safe_subdir(roots, "Films/../../etc") is None
+
+
+def test_safe_subdir_refuses_empty_virtual_root(tmp_path):
+    (tmp_path / "Films").mkdir()
+    roots = RootSet.build([_spec(tmp_path / "Films")])
+    assert safe_subdir(roots, "") is None
+
+
+def test_safe_subdir_refuses_unavailable_root(tmp_path):
+    (tmp_path / "Films").mkdir()
+    roots = RootSet.build([_spec(tmp_path / "Films")])
+    roots.roots[0].available = False
+    assert safe_subdir(roots, "Films/2024") is None