D&D: import Open5e SRD magic items as a vendored reference registry

fetch/gen magicitems subcommands vendor data/open5e/magicitems.json (237
SRD items) and classify them into a generated registry. magic_items.go
holds the MagicItem struct + Kind enum + an init-time overlay merge where
a hand-authored entry wins on ID collision, mirroring the spell and
bestiary imports. Not yet wired into zone loot or the shop — that
integration is a deliberate follow-up.

internal/plugin/magic_items.go

@@ -0,0 +1,67 @@
+package plugin
+
+// Magic items — Open5e SRD import.
+//
+// Per the open5e integration plan, magic items are the one genuinely net-new
+// surface: EquipmentDef is a flavor ladder, not a structured magic-item table,
+// so there is nothing to extend. This file is the single new, non-dnd_-prefixed
+// table the plan allows for them.
+//
+// Like the bestiary staging table, this is a vendored *reference registry* —
+// 237 SRD magic items with classified Kind/Rarity/Slot/attunement and a
+// rarity-bracket sell value. It is deliberately NOT wired into the zone loot
+// tables or Luigi's shop yet; that integration is a separate follow-up pass.
+// buildSRDMagicItems() is the generated dump (see magic_items_srd_data.go);
+// magicItemOverlay is the hand-authored refinement layer that wins on ID
+// collision, mirroring the spell- and bestiary-import pattern.
+
+// MagicItemKind is the coarse Open5e item category — the first word of Open5e's
+// free-text "type" field, normalised.
+type MagicItemKind string
+
+const (
+	MagicItemWondrous MagicItemKind = "wondrous"
+	MagicItemWeapon   MagicItemKind = "weapon"
+	MagicItemArmor    MagicItemKind = "armor"
+	MagicItemRing     MagicItemKind = "ring"
+	MagicItemWand     MagicItemKind = "wand"
+	MagicItemRod      MagicItemKind = "rod"
+	MagicItemStaff    MagicItemKind = "staff"
+	MagicItemPotion   MagicItemKind = "potion"
+	MagicItemScroll   MagicItemKind = "scroll"
+)
+
+// MagicItem is one classified SRD magic item.
+type MagicItem struct {
+	ID         string
+	Name       string
+	Kind       MagicItemKind
+	Rarity     DnDRarity
+	Attunement bool
+	// Slot is a best-effort equip slot. It is "" for consumables (potions,
+	// scrolls) and for wondrous items whose name carries no wearable noun.
+	Slot  DnDSlot
+	Value int    // sell value, derived from the §8.1-aligned rarity bracket
+	Desc  string // first-sentence summary of the SRD description
+}
+
+// magicItemOverlay — hand-authored magic items that win on ID collision with
+// the generated SRD dump. Empty for now: the classifier output is the starting
+// point, and corrections (or wholly new items) land here rather than being
+// edited into the generated file.
+var magicItemOverlay []MagicItem
+
+// magicItemRegistry is the merged lookup table: the generated SRD dump with the
+// hand-authored overlay layered on top.
+var magicItemRegistry = buildMagicItemRegistry()
+
+func buildMagicItemRegistry() map[string]MagicItem {
+	reg := make(map[string]MagicItem)
+	for _, mi := range buildSRDMagicItems() {
+		reg[mi.ID] = mi
+	}
+	for _, mi := range magicItemOverlay {
+		reg[mi.ID] = mi // hand-authored wins
+	}
+	return reg
+}