feat(gems): add multiplayer gem game with custom content packs

- implement FastAPI and HTMX lobby and game interfaces
- support up to four human and AI-controlled players
- add configurable rules, victory conditions, and expansion modules
- support validated JSON cards, patrons, objectives, and outposts

tests/gems/test_modules.py

@@ -0,0 +1,60 @@
+from __future__ import annotations
+
+from python.gems.domain.engine import bonuses, new_game
+from python.gems.domain.models import GameSettings, Modules, OwnedCard, Requirement, RequirementKind, ResourceDefinition
+from python.gems.domain.requirements import requirements_met
+
+
+def test_any_color_requirements_can_be_distinct() -> None:
+    requirements = [
+        Requirement(id="first", kind=RequirementKind.ANY_COLOR, count=2),
+        Requirement(id="second", kind=RequirementKind.ANY_COLOR, count=2, distinct_from=["first"]),
+    ]
+    assert requirements_met(requirements, {"pearl": 2, "wave": 2})
+    assert not requirements_met(requirements, {"pearl": 3, "wave": 1})
+
+
+def test_light_resource_colors_use_dark_token_lettering() -> None:
+    light = ResourceDefinition(id="light", label="Light", symbol="W", color="#f4f2ed")
+    gold = ResourceDefinition(id="gold", label="Gold", symbol="Au", color="#d9a928")
+    dark = ResourceDefinition(id="dark", label="Dark", symbol="B", color="#151719")
+    assert light.ink_color == "#111111"
+    assert gold.ink_color == "#ffffff"
+    assert dark.ink_color == "#ffffff"
+
+
+def test_standard_resources_store_conventional_symbols() -> None:
+    """Standard gem labels normalize legacy abbreviations in pack data."""
+    standard = {
+        "Onyx": "O",
+        "Sapphire": "S",
+        "Emerald": "E",
+        "Ruby": "R",
+        "Diamond": "D",
+        "Gold": "G",
+    }
+
+    for label, expected in standard.items():
+        resource = ResourceDefinition(id=label.casefold(), label=label, symbol="?", color="#334455")
+        assert resource.symbol == expected
+
+    custom = ResourceDefinition(id="pearl", label="Pearl", symbol="P", color="#334455")
+    assert custom.symbol == "P"
+
+
+def test_all_modules_deal_their_content(content_pack) -> None:
+    settings = GameSettings(modules=Modules(objectives=True, outposts=True, eastern_decks=True, fortifications=True))
+    state = new_game("ABCDEFGH", ["A", "B"], content_pack, settings, seed=5)
+    assert "eastern:1" in state.markets
+    assert state.available_objectives == ["goal_one"]
+    assert not state.available_patrons
+    assert state.players[0].fortifications_available == 3
+
+
+def test_multi_bonus_counts_twice_but_is_one_card(content_pack) -> None:
+    settings = GameSettings(modules=Modules(eastern_decks=True))
+    state = new_game("ABCDEFGH", ["A"], content_pack, settings, seed=5)
+    player = state.players[0]
+    player.cards.append(OwnedCard(card_id="eastern_2_1"))
+    assert bonuses(player, content_pack)[content_pack.card("eastern_2_1").bonus_resource] == 2
+    assert len(player.cards) == 1