chore: rebrand ClubManager -> RosterChief, add lucide icons

The clubmanager.app domain was taken, so the platform is now RosterChief
(rosterchief.app). Renames the Django project package clubmanager/ ->
rosterchief/ (git tracks it as a move, so history follows), every
`from rosterchief.base import ...`, the settings/wsgi/asgi module paths,
env vars (ROSTERCHIEF_BASE_DOMAIN / ROSTERCHIEF_RP_NAME), the MFA adapter
(RosterChiefMFAAdapter), brand text, and the docs.

Two things were deliberately NOT swept:
- club.models.ClubManager stays: it is the Django manager *for Club*, not the
  brand. A blind rename would have silently broken it.
- Migrations are untouched (history is not rewritten). The only reference was a
  cosmetic help_text, so a normal AlterField migration carries the new domain.

Note the WebAuthn RP ID is the base domain, so moving to rosterchief.app
cryptographically invalidates any passkey enrolled under the old one; they
cannot be migrated and must be re-enrolled. Nothing is in production, so the
real cost is zero.

Add django-lucide (from bsiebens/lucide) for icons: the theme toggle now swaps
sun/moon against the effective theme, and the control panel gets icons on its
tabs, actions and stat groups. Its classifiers stop at Django 5.0, but that is
stale metadata — verified rendering on Django 6 / Python 3.14.

Also add formbuilder, shop and controlpanel to ruff's known-first-party list,
which had drifted behind the apps that landed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pyproject.toml

@@ -1,11 +1,12 @@
 [project]
-name = "clubmanager"
+name = "rosterchief"
 version = "0.1.0"
 requires-python = ">=3.14"
 dependencies = [
     "dj-database-url>=3.1.2",
     "django>=6.0.6",
     "django-allauth[mfa]>=65.18.0",
+    "django-lucide",
     "django-phonenumber-field[phonenumbers]>=8.4.0",
     "pillow>=12.3.0",
     "python-dateutil>=2.9.0.post0",
@@ -43,7 +44,10 @@ ignore = [
 
 [tool.ruff.lint.per-file-ignores]
 # Settings legitimately use star imports and long generated values.
-"clubmanager/settings/*" = ["F403", "F405", "E501"]
+"rosterchief/settings/*" = ["F403", "F405", "E501"]
 
 [tool.ruff.lint.isort]
-known-first-party = ["authentication", "club", "members", "teams", "events", "news", "pages", "home", "search", "clubmanager"]
+known-first-party = ["authentication", "club", "members", "teams", "events", "formbuilder", "shop", "controlpanel", "news", "pages", "home", "search", "rosterchief"]
+
+[tool.uv.sources]
+django-lucide = { git = "https://github.com/bsiebens/lucide" }