feat(combat): add concealment miss chance, sneak attack, and Precise Shot

tests/test_observation_enriched.py

@@ -1232,7 +1232,7 @@ def test_observation_enriched_condition_definitions_present() -> None:
     """Given: an Observation built over any combat
     When: the top-level dict is inspected
     Then: condition_definitions is a sorted tuple of (name, {mods, flags,
-    speed_mult}) covering every entry of CONDITIONS_BY_NAME."""
+    speed_mult, miss_chance}) covering every entry of CONDITIONS_BY_NAME."""
     hero = make_combatant("hero")
     foe = make_combatant("foe")
     hero_state = make_state(hero, "players", (0, 0))
@@ -1246,10 +1246,11 @@ def test_observation_enriched_condition_definitions_present() -> None:
     # Sorted by name for determinism.
     assert [n for n, _ in defs] == sorted(CONDITIONS_BY_NAME)
     for _name, body in defs:
-        assert set(body) == {"mods", "flags", "speed_mult"}
+        assert set(body) == {"mods", "flags", "speed_mult", "miss_chance"}
         assert isinstance(body["mods"], list)
         assert isinstance(body["flags"], list)
         assert isinstance(body["speed_mult"], float)
+        assert isinstance(body["miss_chance"], int)
 
 
 def test_observation_enriched_condition_definitions_shaken() -> None: