feat(custom-rulesets): support custom rulesets (#23)

* feat(custom_ruleset): add custom rulesets support

* feat(custom-ruleset): add version check

* feat(custom-ruleset): add LegacyIO API to get ruleset hashes

* feat(pp): add check for rulesets whose pp cannot be calculated

* docs(readme): update README to include support for custom rulesets

* fix(custom-ruleset): make `rulesets` empty instead of throw a error when version check is disabled

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* chore(custom-ruleset): apply the latest changes of generator

c891bcd159

and

e25041ad3b

* feat(calculator): add fallback performance calculation for unsupported modes

* fix(calculator): remove debug print

* fix: resolve reviews

* feat(calculator): add difficulty calculation checks

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

app/calculators/performance/_base.py

@@ -1,5 +1,5 @@
 import abc
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, NamedTuple
 
 from app.models.mods import APIMod
 from app.models.performance import DifficultyAttributes, PerformanceAttributes
@@ -25,7 +25,16 @@ class PerformanceError(CalculateError):
     """The performance could not be calculated."""
 
 
+class AvailableModes(NamedTuple):
+    has_performance_calculator: set[GameMode]
+    has_difficulty_calculator: set[GameMode]
+
+
 class PerformanceCalculator(abc.ABC):
+    @abc.abstractmethod
+    async def get_available_modes(self) -> AvailableModes:
+        raise NotImplementedError
+
     @abc.abstractmethod
     async def calculate_performance(self, beatmap_raw: str, score: "Score") -> PerformanceAttributes:
         raise NotImplementedError
@@ -35,3 +44,15 @@ class PerformanceCalculator(abc.ABC):
         self, beatmap_raw: str, mods: list[APIMod] | None = None, gamemode: GameMode | None = None
     ) -> DifficultyAttributes:
         raise NotImplementedError
+
+    async def can_calculate_performance(self, gamemode: GameMode) -> bool:
+        modes = await self.get_available_modes()
+        return gamemode in modes.has_performance_calculator
+
+    async def can_calculate_difficulty(self, gamemode: GameMode) -> bool:
+        modes = await self.get_available_modes()
+        return gamemode in modes.has_difficulty_calculator
+
+    async def init(self) -> None:
+        """Initialize the calculator (if needed)."""
+        pass