Add accounts app: custom User, Member, families & guardianship

Introduce the foundational accounts app:
- Custom email-as-username User (AbstractBaseUser + PermissionsMixin) set
  as AUTH_USER_MODEL, decoupled from membership so children can be members
  without a login.
- Member model holding personal/roster data (names, contact email, phone +
  emergency phone via django-phonenumber-field, license number, DOB) with an
  optional link to a User.
- Family household grouping and directional Guardianship (guardian -> child)
  with uniqueness and no-self-guardian constraints.
- Custom UserAdmin plus Member/Family admin with inlines and autocomplete.
- Settings: register apps, AUTH_USER_MODEL, phonenumber defaults (BE/E164).
- Add CLAUDE.md and a tracked static/ directory.

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

accounts/models.py

@@ -0,0 +1,140 @@
+from django.conf import settings
+from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin
+from django.db import models
+from django.utils import timezone
+from phonenumber_field.modelfields import PhoneNumberField
+
+from .managers import UserManager
+
+
+class User(AbstractBaseUser, PermissionsMixin):
+    """Login identity. Only people who actually sign in get a User.
+
+    Personal/roster data lives on :class:`Member`; this model carries just the
+    authentication identity. ``PermissionsMixin`` provides ``is_superuser``,
+    ``groups`` and ``user_permissions`` (the basis for the access tiers).
+    """
+
+    email = models.EmailField(unique=True)
+    is_staff = models.BooleanField(
+        default=False,
+        help_text="Whether the user can log into the admin site.",
+    )
+    is_active = models.BooleanField(default=True)
+    date_joined = models.DateTimeField(default=timezone.now)
+
+    objects = UserManager()
+
+    USERNAME_FIELD = "email"
+    REQUIRED_FIELDS = []
+
+    def __str__(self):
+        return self.get_full_name()
+
+    def get_full_name(self):
+        member = getattr(self, "member", None)
+        if member is not None:
+            return f"{member.first_name} {member.last_name}".strip()
+        return self.email
+
+    def get_short_name(self):
+        member = getattr(self, "member", None)
+        if member is not None:
+            return member.first_name
+        return self.email
+
+
+class Family(models.Model):
+    """A household grouping members together."""
+
+    name = models.CharField(max_length=150, help_text='e.g. "The Smiths"')
+    address = models.CharField(max_length=255, blank=True)
+
+    class Meta:
+        ordering = ["name"]
+        verbose_name_plural = "families"
+
+    def __str__(self):
+        return self.name
+
+
+class Member(models.Model):
+    """A person in the club. May or may not have a login (:attr:`user`)."""
+
+    user = models.OneToOneField(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.SET_NULL,
+        null=True,
+        blank=True,
+        related_name="member",
+    )
+
+    first_name = models.CharField(max_length=150)
+    last_name = models.CharField(max_length=150)
+    # Contact email — optional. Children may have none; a login email lives on User.
+    email = models.EmailField(blank=True)
+    phone = PhoneNumberField(blank=True)
+    emergency_phone = PhoneNumberField(blank=True)
+    license_number = models.CharField(max_length=50, blank=True)
+    date_of_birth = models.DateField()
+
+    family = models.ForeignKey(
+        Family,
+        on_delete=models.SET_NULL,
+        null=True,
+        blank=True,
+        related_name="members",
+    )
+    guardians = models.ManyToManyField(
+        "self",
+        through="Guardianship",
+        through_fields=("child", "guardian"),
+        symmetrical=False,
+        related_name="dependents",
+    )
+
+    class Meta:
+        ordering = ["last_name", "first_name"]
+
+    def __str__(self):
+        return f"{self.first_name} {self.last_name}"
+
+
+class Guardianship(models.Model):
+    """Directional guardian -> child relationship between two members."""
+
+    class Relationship(models.TextChoices):
+        PARENT = "parent", "Parent"
+        GUARDIAN = "guardian", "Guardian"
+        OTHER = "other", "Other"
+
+    guardian = models.ForeignKey(
+        Member,
+        on_delete=models.CASCADE,
+        related_name="guardian_links",
+    )
+    child = models.ForeignKey(
+        Member,
+        on_delete=models.CASCADE,
+        related_name="child_links",
+    )
+    relationship = models.CharField(
+        max_length=20,
+        choices=Relationship.choices,
+        default=Relationship.PARENT,
+    )
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(
+                fields=["guardian", "child"],
+                name="unique_guardianship",
+            ),
+            models.CheckConstraint(
+                condition=~models.Q(guardian=models.F("child")),
+                name="guardian_not_self",
+            ),
+        ]
+
+    def __str__(self):
+        return f"{self.guardian} → {self.child} ({self.get_relationship_display()})"