Add complete database schema and ORM models (#4)

internal/models/channel_member.go

@@ -0,0 +1,36 @@
+package models
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// ChannelMember represents a user's membership in a channel.
+type ChannelMember struct {
+	Base
+
+	ChannelID string    `json:"channelId"`
+	UserID    string    `json:"userId"`
+	Modes     string    `json:"modes"`
+	JoinedAt  time.Time `json:"joinedAt"`
+	Nick      string    `json:"nick"` // denormalized from users table
+}
+
+// User returns the full User for this membership.
+func (cm *ChannelMember) User(ctx context.Context) (*User, error) {
+	if ul := cm.GetUserLookup(); ul != nil {
+		return ul.GetUserByID(ctx, cm.UserID)
+	}
+
+	return nil, fmt.Errorf("user lookup not available")
+}
+
+// Channel returns the full Channel for this membership.
+func (cm *ChannelMember) Channel(ctx context.Context) (*Channel, error) {
+	if cl := cm.GetChannelLookup(); cl != nil {
+		return cl.GetChannelByID(ctx, cm.ChannelID)
+	}
+
+	return nil, fmt.Errorf("channel lookup not available")
+}