Add WOTD language rotation, fancy word detection, arena improvements, and death consolidation

- Rotate WOTD between Portuguese, French, and English daily with cognate filtering
- Replace LLM-based fancy word detection with DreamDict frequency data (batch API + cache)
- Track fancy word usage per user and add Wordsmith archetype
- Restore full arena combat flavor text and add player miss actions
- Consolidate death logic into Kill() method with 2-hour lockout
- Fix arena death XP grant missing level-up check
- Fix LLM wotd_used classification by injecting actual WOTD into prompt

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/plugin/adventure_character.go

@@ -195,6 +195,13 @@ func (c *AdventureCharacter) DeathReprieveAvailable() bool {
 	return time.Since(*c.DeathReprieveLast) >= 168*time.Hour
 }
 
+// Kill marks the character as dead with a 2-hour respawn timer.
+func (c *AdventureCharacter) Kill() {
+	c.Alive = false
+	deadUntil := time.Now().UTC().Add(2 * time.Hour)
+	c.DeadUntil = &deadUntil
+}
+
 // ── Equipment Score ──────────────────────────────────────────────────────────
 
 func advEquipmentScore(equip map[EquipmentSlot]*AdvEquipment) int {