feat: allow available equipment list definition for content pack fighters

[tgvashworth]

Summary

Content pack creators can define custom fighters, but there's no way to specify which equipment those fighters are allowed to take. The ContentFighterEquipmentListItem model supports this for base-game fighters, but the pack UI doesn't expose it.

Problem

Without an available equipment list, custom pack fighters either have access to everything or nothing (depending on how the system falls back). Pack creators need to curate what equipment is appropriate for their custom fighter types — e.g. a custom juve shouldn't have access to heavy weapons.

Desired behaviour

Pack creators should be able to define an equipment list for their custom fighters, specifying:

• Which equipment items are available (from the pack's own custom equipment and/or the base game)
• Optional cost overrides per fighter type (a weapon might cost more for one fighter category than another)
• Category restrictions if applicable

This mirrors what ContentFighterEquipmentListItem already does for base-game fighters in the admin.

Current architecture

• ContentFighterEquipmentListItem (in content/models/equipment_list.py) links a ContentFighter to available ContentEquipment with optional cost overrides and category scoping
• The equipment assignment UI already checks available equipment lists when adding gear to a fighter
• Pack equipment items are ContentEquipment instances scoped to a pack via CustomContentPackItem
• The equipment list needs to support both pack-scoped and base-game equipment references

Implementation notes

• UI could be a separate tab/section on the pack fighter edit page, or a dedicated "Equipment list" sub-page
• Should support mixing pack equipment and base-game equipment in the same list
• Cost override support would be valuable but could be a follow-up
• Consider how this interacts with house-level equipment lists (some houses restrict available equipment)

Related

• See also: default equipment definition for pack fighters (separate issue)

[claude]

Implementation Plan

The existing ContentFighterEquipmentListItem model already supports everything needed — the gap is purely in the pack UI layer.

Files to Modify

• gyrinx/core/views/pack.py — Add a new view for managing a fighter's equipment list (list/add/remove items). Wire it into the existing edit_pack_item flow or as a separate sub-page linked from the fighter edit page.
• gyrinx/core/urls.py — Add URL pattern for the equipment list management page (e.g. /packs/<id>/item/<item_id>/equipment-list/).
• gyrinx/core/forms/pack.py — Add a form for ContentFighterEquipmentListItem creation scoped to a pack. The equipment queryset needs ContentEquipment.objects.with_packs([pack]) to show both base-game and pack equipment.
• gyrinx/core/templates/core/pack/pack_item_edit.html — Add a link/section to the equipment list sub-page for fighter items.
• New template: gyrinx/core/templates/core/pack/pack_fighter_equipment_list.html — The equipment list management page showing current items with add/remove controls.

Approach

1. New view pack_fighter_equipment_list(request, id, item_id) that:
   • Verifies pack edit permission
   • Lists existing ContentFighterEquipmentListItem entries for the fighter
   • Provides add form with equipment filtered via with_packs([pack]) (base-game + pack equipment)
   • Handles removal of items
2. Form with equipment field (filtered queryset), optional weapon_profile (filtered to selected equipment's profiles), and cost override field
3. Link from fighter edit page — add a "Equipment List" link/button on the fighter edit page that navigates to the sub-page
4. Tests covering add/remove/duplicate prevention and permission checks

Considerations

• The unique_together = ["fighter", "equipment", "weapon_profile"] constraint on ContentFighterEquipmentListItem handles duplicate prevention naturally
• Cost overrides could be included in V1 since the model already supports it (just a cost field on the form) — no reason to defer
• Weapon profile selection adds UI complexity (dependent dropdown) — could start with equipment-only and add profile selection as a fast follow
• ContentFighterEquipmentListItem entries created here don't need to be wrapped as CustomContentPackItem themselves — they reference content objects that are already pack items
• House-level equipment list interaction: pack fighters inherit their house's equipment restrictions via the existing equipment_list_fighters logic, so this feature layers on top correctly