feat(enemy): sistema d'HP declaratiu i nou enemic big_pentagon

data/entities/big_pentagon/big_pentagon.yaml

@@ -0,0 +1,79 @@
+name: big_pentagon
+ai_type: big_pentagon       # Validat contra el directori; mapeja a EnemyType::BIG_PENTAGON.
+
+# Reusa la shape de pentagon però a escala 2.0 — primer enemic gegant del joc.
+shape:
+  path: enemy_pentagon.shp
+  scale: 2.0
+  collision_factor: 1.0
+
+physics:
+  mass: 20.0                 # Massa gran: la bala el frena poc, els trossos volen amb la força de la bala.
+  speed: 30.0                # Avanç lent, com a "tanc carregant".
+  rotation_delta_min: 0.3
+  rotation_delta_max: 1.5
+  restitution: 1.0
+  linear_damping: 0.0
+  angular_damping: 0.0
+
+ai:
+  # Persecució lenta del ship més proper: amb chase_strength baix la inèrcia
+  # és molt notable, fa el comportament del "boss lent" característic.
+  movement:
+    type: chase
+    chase_strength: 0.3
+
+animation:
+  pulse:
+    trigger_prob_per_second: 0.01
+    duration_min: 1.0
+    duration_max: 3.0
+    amplitude_min: 0.08
+    amplitude_max: 0.20
+    frequency_min: 1.5
+    frequency_max: 3.0
+  rotation_accel:
+    trigger_prob_per_second: 0.02
+    duration_min: 3.0
+    duration_max: 8.0
+    multiplier_min: 0.3
+    multiplier_max: 4.0
+
+wounded:
+  duration: 1.5              # Una mica més llarg que els altres (és un boss).
+  blink_hz: 10.0
+
+spawn:
+  invulnerability_duration: 3.0
+  invulnerability_brightness_start: 0.3
+  invulnerability_brightness_end: 0.7
+  invulnerability_scale_start: 0.0
+  invulnerability_scale_end: 1.0
+  safety_distance: 72.0      # Doble del normal — és el doble de gran.
+
+colors:
+  normal:  [0, 180, 255]     # Blau elèctric per distingir-lo del pentagon cyan.
+  wounded: [255, 220, 60]
+
+score: 500                   # 5x un enemic normal: aguanta 10x més.
+
+# Estrenant el sistema HP: 10 unitats. Cada bala fa decrease_health + flash
+# + create_debris_partial (xip a 0.3x). En el 10è hit, on_no_health
+# encadena set_hurt (entra wounded). Wound expira → destroy → on_destroy
+# fa l'explosió completa.
+health: 10
+
+events:
+  on_hit:
+    - action: decrease_health      # primer: si arriba a 0 dispara on_no_health
+    - action: flash                # feedback visual de damage parcial
+    - action: create_debris_partial # xip a 0.3x mida (sense ser letal)
+    - action: apply_impulse        # empenta el cos (sense will_die és segur en hit no-letal)
+  on_no_health:
+    - action: set_hurt             # entra wounded; segon hit durant wounded matarà
+  on_hurt_end:
+    - action: destroy
+  on_destroy:
+    - action: add_score
+    - action: create_debris        # explosió completa
+    - action: create_fireworks

data/entities/pentagon/pentagon.yaml

@@ -55,10 +55,14 @@ colors:
 score: 100
 
 events:
-  # Comportament clàssic: dos impactes per matar (set_hurt entra wounded;
-  # el segon hit detecta wounded i destrueix automàticament).
+  # HP=1 (default): decrement → on_no_health → set_hurt → wounded → mort.
+  # decrease_health primer perquè si la mort cau aquí (segon hit durant wounded),
+  # el dispatcher salta la resta del chain (incloent apply_impulse) sobre el
+  # cos ja destruït.
   on_hit:
+    - action: decrease_health
     - action: apply_impulse
+  on_no_health:
     - action: set_hurt
   on_hurt_end:
     - action: destroy

data/entities/pinwheel/pinwheel.yaml

@@ -55,8 +55,11 @@ colors:
 score: 200
 
 events:
+  # HP=1 (default): decrement → on_no_health → set_hurt → wounded → mort.
   on_hit:
+    - action: decrease_health
     - action: apply_impulse
+  on_no_health:
     - action: set_hurt
   on_hurt_end:
     - action: destroy

data/entities/square/square.yaml

@@ -56,8 +56,11 @@ colors:
 score: 150
 
 events:
+  # HP=1 (default): decrement → on_no_health → set_hurt → wounded → mort.
   on_hit:
+    - action: decrease_health
     - action: apply_impulse
+  on_no_health:
     - action: set_hurt
   on_hurt_end:
     - action: destroy

data/entities/star/star.yaml

@@ -66,8 +66,10 @@ score: 100
 
 events:
   # STAR: mor al primer impacte, sense passar per wounded.
+  # HP=1 (default): decrement → on_no_health → destroy directe (sense wounded).
   on_hit:
-    - action: apply_impulse
+    - action: decrease_health
+  on_no_health:
     - action: destroy
   on_destroy:
     - action: add_score

data/stages/stages.yaml

@@ -7,7 +7,7 @@ metadata:
   description: "Progressive difficulty curve from novice to expert"
 
 stages:
-  # STAGE 1: Tutorial - Mix de tots 4 tipus al 25% per mostrar-los junts
+  # STAGE 1: Tutorial - Mix de tots 5 tipus per mostrar-los junts (inclou big_pentagon)
   - stage_id: 1
     total_enemies: 50
     spawn_config:
@@ -15,10 +15,11 @@ stages:
       initial_delay: 0.3
       spawn_interval: 0.4
     enemy_distribution:
-      pentagon: 25
-      cuadrado: 25
-      molinillo: 25
-      star: 25
+      pentagon: 20
+      cuadrado: 20
+      molinillo: 20
+      star: 20
+      big_pentagon: 20
     difficulty_multipliers:
       speed_multiplier: 0.7
       rotation_multiplier: 0.8