feat(hub): split the group UI into a pluggable "applications" architecture

GroupPage's 6620-line app.js carried Chat and Files wedged in directly, with
no way to add another group-level app without touching the shell itself. It
is now app.js (routing, non-group pages) plus nine focused files — apps.js
(the registry), chat-app.js, files-app.js, video-player.js, group-page.js
(the shell), group-settings.js, hub-client.js, icon.js and file-utils.js —
with docs/apps.md as the checklist for adding one (Videos/Music/Photos are
sketched there, not built).

Node side gained the matching enablement mechanism, mirroring
member_upload exactly: a roster setting, a signed apps_enabled op enforced
by _has_admin_authority, exposed in the handshake ack. Operators toggle
applications per group from Settings, which also gained a small reorder:
Invite, Pairing, Applications, Shared directories, Uploads, danger zone,
Your devices, Members.

Two bugs surfaced during the split, both missing an import across the new
file boundary and invisible to node --check or a module-load probe since
they only throw when the code path actually runs:

- group-page.js called onRefreshAuth on a stale-token handshake rejection,
  but app.js never imported refreshAccessToken from hub-client.js — so a
  brand new member (including a group's own creator) hit "Not a member of
  this group" and the retry silently failed, throwing before it could
  refresh the token.
- chat-app.js called getLocale() for message timestamps without importing
  it from i18n.js. Opening Chat on a group with real messages threw mid-
  render; uncaught, that appears to wedge Preact's render scheduler, so
  every button on the page stopped responding until reload.

Caught the second class of bug with a proper no-undef audit across all
split files (a temporarily installed ESLint 9, since the system one is too
old to parse this codebase's syntax) rather than trusting grep. 827 tests
pass; 6 new ones cover the apps_enabled policy.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016SF6RKNBKg9qejmoMJ9ybA

1 files changed, 31 insertions, 10 deletions

diff --git a/packages/meshbay-hub/tests/test_hook_ordering.py b/packages/meshbay-hub/tests/test_hook_ordering.py
index cd9a11e..dac1357 100644
--- a/packages/meshbay-hub/tests/test_hook_ordering.py
+++ b/packages/meshbay-hub/tests/test_hook_ordering.py
@@ -26,6 +26,17 @@ import pytest
 STATIC = Path(__file__).resolve().parents[1] / "src" / "meshbay_hub" / "static"
 APP = STATIC / "app.js"
 
+# One monolithic app.js used to hold every component; the group-page refactor
+# split it into one file per "application" (chat-app.js, files-app.js,
+# video-player.js, group-settings.js) plus the group shell (group-page.js).
+# A future Videos/Music/Photos app lands in its own file the same way — add it
+# here so this test keeps seeing it, since `_all_components` below only walks
+# the files named in this list.
+STATIC_FILES = [
+    "app.js", "group-page.js", "chat-app.js", "files-app.js",
+    "video-player.js", "group-settings.js",
+]
+
 pytestmark = pytest.mark.skipif(not APP.exists(), reason="SPA sources unavailable")
 
 # `const NAME = useCallback(` / `useMemo(` — the declarations that both define a
@@ -40,18 +51,28 @@ def app():
     return APP.read_text()
 
 
-def _components(app: str):
-    """Each top-level component, with the offset it starts at."""
-    for m in re.finditer(r"^function ([A-Z]\w*)\(", app, re.M):
+def _components(src: str):
+    """Each top-level component in one file, with the offset it starts at."""
+    for m in re.finditer(r"^function ([A-Z]\w*)\(", src, re.M):
         start = m.start()
-        nxt = app.find("\nfunction ", start + 1)
-        yield m.group(1), app[start:nxt if nxt > 0 else len(app)]
+        nxt = src.find("\nfunction ", start + 1)
+        yield m.group(1), src[start:nxt if nxt > 0 else len(src)]
+
+
+def _all_components():
+    """Every top-level component across every static file that can hold one."""
+    for name in STATIC_FILES:
+        path = STATIC / name
+        if not path.exists():
+            continue
+        for cname, body in _components(path.read_text()):
+            yield f"{name}:{cname}", body
 
 
-def test_no_hook_depends_on_something_declared_below_it(app):
-    """The whole file, not just the player that was broken by it."""
+def test_no_hook_depends_on_something_declared_below_it():
+    """Every static file that can hold a component, not just app.js."""
     problems = []
-    for name, body in _components(app):
+    for name, body in _all_components():
         # Where each hook binding becomes usable.
         declared_at = {m.group(1): m.start() for m in DECL.finditer(body)}
         for deps in DEPS.finditer(body):
@@ -68,13 +89,13 @@ def test_no_hook_depends_on_something_declared_below_it(app):
         + "\n  ".join(problems))
 
 
-def test_the_check_would_notice(app):
+def test_the_check_would_notice():
     """A test that cannot fail proves nothing — so make it fail on purpose.
 
     Swaps two declarations in the real file and confirms the rule fires. If
     this stops working the rule above has quietly become decoration.
     """
-    body = next(b for n, b in _components(app) if n == "VideoPlayer")
+    body = next(b for n, b in _all_components() if n == "video-player.js:VideoPlayer")
     decls = list(DECL.finditer(body))
     assert len(decls) >= 2, "VideoPlayer has too few hooks to test the check"