feat: default_label_resolver reads name property; item-template convention

The default label_resolver now reads the optional player-facing `name`
property from the item-template; modules with named templates get pretty
row labels without registering an override. Falls back to "Item" when
`name` is absent or empty.

README documents the player-facing item-template convention: name,
description, weight, volume, composition.<material> — all optional,
all with documented defaults. Skill-gated description reveals stay on
the separate hints lib (designed, not yet implemented).

init.lua

@@ -81,9 +81,14 @@ local function default_icon_resolver(item)
 end
 
 -- default_label_resolver(item) -> string
--- v0.1: no public composition.template_of accessor exists. Module
--- overrides via set_label_resolver to provide pretty names.
+-- Reads the player-facing `name` property from the item-template. Modules
+-- that declare `name` on their item-templates get pretty names automatically;
+-- modules without `name` get the generic "Item" fallback.
+-- Override via set_label_resolver for custom mappings (template-id, lookup
+-- table, localization, …).
 local function default_label_resolver(item)
+    local name = item:get_property("name")
+    if name and name ~= "" then return name end
     return "Item"
 end