Give every NPC a race and class, resolved at spawn time

NPCs can now optionally specify race and class in their TOML. When
omitted, race is randomly selected from non-hidden races and class is
determined by the race's default_class or picked randomly from
compatible non-hidden classes. Race/class are re-rolled on each
respawn for NPCs without fixed values, so killing the barkeep may
bring back a different race next time.

New hidden content (excluded from character creation):
- Beast race: for animals (rats, etc.) with feral stats and no
  equipment slots
- Peasant class: weak default for humanoid NPCs
- Creature class: default for beasts/animals

Existing races gain default_class fields (humanoids → peasant,
beast → creature, dragon → random compatible). Look and examine
commands now display NPC race and class.

Made-with: Cursor

AGENTS.md

@@ -84,11 +84,21 @@ src/
 2. Currently: hostile NPCs auto-engage players in their room
 3. Add new behaviors there (e.g. NPC movement, dialogue triggers)
 
+### New NPC
+1. Create `world/<region>/npcs/<name>.toml`
+2. Optional `race` and `class` fields pin the NPC to a specific race/class
+3. If omitted, race is randomly chosen from non-hidden races at spawn time
+4. If class is omitted, the race's `default_class` is used; if that's also unset, a random non-hidden class is picked
+5. Race/class are re-rolled on each respawn for NPCs without fixed values
+6. For animals: use `race = "race:beast"` and `class = "class:creature"`
+
 ### New race
 1. Create `world/races/<name>.toml` — see `dragon.toml` for a complex example
 2. Required: `name`, `description`
 3. All other fields have sensible defaults via `#[serde(default)]`
 4. Key sections: `[stats]` (7 stats), `[body]` (size, weight, slots), `[natural]` (armor, attacks), `[resistances]`, `[regen]`, `[misc]`, `[guild_compatibility]`
+5. Set `hidden = true` for NPC-only races (e.g., `beast`) to exclude from character creation
+6. Set `default_class` to reference a class ID for the race's default NPC class
 5. `traits` and `disadvantages` are free-form string arrays
 6. If `[body] slots` is empty, defaults to humanoid slots
 7. Natural attacks: use `[natural.attacks.<name>]` with `damage`, `type`, optional `cooldown_ticks`