feat: implement automatic cycle generation for members

- Add CycleGenerator module with advisory lock mechanism
- Add SetMembershipFeeStartDate change for auto-calculation
- Extend Settings with include_joining_cycle and default_membership_fee_type_id
- Add scheduled job skeleton for future Oban integration

lib/membership/setting.ex

@@ -4,13 +4,15 @@ defmodule Mv.Membership.Setting do
 
   ## Overview
   Settings is a singleton resource that stores global configuration for the association,
-  such as the club name and branding information. There should only ever be one settings
-  record in the database.
+  such as the club name, branding information, and membership fee settings. There should
+  only ever be one settings record in the database.
 
   ## Attributes
   - `club_name` - The name of the association/club (required, cannot be empty)
   - `member_field_visibility` - JSONB map storing visibility configuration for member fields
     (e.g., `%{"street" => false, "house_number" => false}`). Fields not in the map default to `true`.
+  - `include_joining_cycle` - Whether to include the joining cycle in membership fee generation (default: true)
+  - `default_membership_fee_type_id` - Default membership fee type for new members (optional)
 
   ## Singleton Pattern
   This resource uses a singleton pattern - there should only be one settings record.
@@ -22,6 +24,12 @@ defmodule Mv.Membership.Setting do
   If set, the environment variable value is used as a fallback when no database
   value exists. Database values always take precedence over environment variables.
 
+  ## Membership Fee Settings
+  - `include_joining_cycle`: When true, members pay from their joining cycle. When false,
+    they pay from the next full cycle after joining.
+  - `default_membership_fee_type_id`: The membership fee type automatically assigned to
+    new members. Can be nil if no default is set.
+
   ## Examples
 
       # Get current settings
@@ -33,6 +41,9 @@ defmodule Mv.Membership.Setting do
 
       # Update member field visibility
       {:ok, updated} = Mv.Membership.update_member_field_visibility(settings, %{"street" => false, "house_number" => false})
+
+      # Update membership fee settings
+      {:ok, updated} = Mv.Membership.update_settings(settings, %{include_joining_cycle: false})
   """
   use Ash.Resource,
     domain: Mv.Membership,
@@ -54,13 +65,24 @@ defmodule Mv.Membership.Setting do
     # Used only as fallback in get_settings/0 if settings don't exist
     # Settings should normally be created via seed script
     create :create do
-      accept [:club_name, :member_field_visibility]
+      accept [
+        :club_name,
+        :member_field_visibility,
+        :include_joining_cycle,
+        :default_membership_fee_type_id
+      ]
     end
 
     update :update do
       primary? true
       require_atomic? false
-      accept [:club_name, :member_field_visibility]
+
+      accept [
+        :club_name,
+        :member_field_visibility,
+        :include_joining_cycle,
+        :default_membership_fee_type_id
+      ]
     end
 
     update :update_member_field_visibility do
@@ -68,6 +90,12 @@ defmodule Mv.Membership.Setting do
       require_atomic? false
       accept [:member_field_visibility]
     end
+
+    update :update_membership_fee_settings do
+      description "Updates the membership fee configuration"
+      require_atomic? false
+      accept [:include_joining_cycle, :default_membership_fee_type_id]
+    end
   end
 
   validations do
@@ -133,6 +161,26 @@ defmodule Mv.Membership.Setting do
       description:
         "Configuration for member field visibility in overview (JSONB map). Keys are member field names (atoms), values are booleans."
 
+    # Membership fee settings
+    attribute :include_joining_cycle, :boolean do
+      allow_nil? false
+      default true
+      public? true
+      description "Whether to include the joining cycle in membership fee generation"
+    end
+
+    attribute :default_membership_fee_type_id, :uuid do
+      allow_nil? true
+      public? true
+      description "Default membership fee type ID for new members"
+    end
+
     timestamps()
   end
+
+  relationships do
+    # Optional relationship to the default membership fee type
+    # Note: We use manual FK (default_membership_fee_type_id attribute) instead of belongs_to
+    # to avoid circular dependency between Membership and MembershipFees domains
+  end
 end