feat(rules): restrict bless to allies in a 50-ft burst

SRD spells/bless.md: 'The caster and all allies within a 50-ft. burst,
centered on the caster'. Add an AreaEffect.targets filter (all/allies/
enemies) applied where area creatures are collected; bless.json now
declares radius_ft 50 and targets allies (the caster included).

tests/test_spells.py

@@ -635,6 +635,50 @@ class TestBullsStrength:
         assert any("buff" in line for line in engine._transcript)
 
 
+class TestBlessAlliesOnly:
+    """Given: a caster casting Bless (SRD: 50-ft burst, "the caster and all
+    allies")
+    When: _cast_spell is called
+    Then: the caster and allies inside the burst are buffed, enemies inside
+    the burst are not."""
+
+    def _bless_engine(
+        self,
+    ) -> tuple[CombatEngine, CombatantState, CombatantState, CombatantState]:
+        caster = _make_caster()
+        ally = _make_target("ally", hp_max=20)
+        enemy = _make_target("enemy", hp_max=20)
+        c = CombatantState(combatant=caster, side="players", pos=(0, 0), hp=caster.hp_max)
+        a = CombatantState(combatant=ally, side="players", pos=(1, 0), hp=ally.hp_max)
+        e = CombatantState(combatant=enemy, side="monsters", pos=(2, 0), hp=enemy.hp_max)
+        legend = {".": TerrainType(type="floor", move_cost=1)}
+        spec = MapSpec(name="test", terrain=tuple(["." * 12] * 12), legend=legend)
+        grid = Grid.from_spec(spec)
+        engine = CombatEngine(
+            ScriptedRng([]), grid, [c, a, e],
+            spell_registry=load_spell_registry(_SPELLS_DIR),
+        )
+        return engine, c, a, e
+
+    def test_allies_buffed_enemy_not(self) -> None:
+        engine, c, a, e = self._bless_engine()
+        engine._cast_spell(c, c, "Bless")
+        caster_buffs = [m for b in c.active_buffs for m in b.modifiers]
+        ally_buffs = [m for b in a.active_buffs for m in b.modifiers]
+        assert any(m.target == "attack" and m.value == 1 for m in caster_buffs)
+        assert any(m.target == "attack" and m.value == 1 for m in ally_buffs)
+        assert not e.active_buffs
+
+    def test_enemy_outside_burst_unaffected(self) -> None:
+        engine, c, a, e = self._bless_engine()
+        # Move the enemy beyond the 50-ft burst (10 cells) before casting.
+        e.pos = (11, 0)
+        engine._cast_spell(c, c, "Bless")
+        assert not e.active_buffs
+        assert any(m.target == "attack" and m.value == 1
+                   for b in c.active_buffs for m in b.modifiers)
+
+
 class TestOutOfRange:
     """Given: a target beyond the spell's maximum range
     When: _cast_spell is called