[red-knot] Initial support for dataclasses (#17353)

## Summary

Add very early support for dataclasses. This is mostly to make sure that
we do not emit false positives on dataclass construction, but it also
lies some foundations for future extensions.

This seems like a good initial step to merge to me, as it basically
removes all false positives on dataclass constructor calls. This allows
us to use the ecosystem checks for making sure we don't introduce new
false positives as we continue to work on dataclasses.

## Ecosystem analysis

I re-ran the mypy_primer evaluation of [the `__init__`
PR](https://github.com/astral-sh/ruff/pull/16512) locally with our
current mypy_primer version and project selection. It introduced 1597
new diagnostics. Filtering those by searching for `__init__` and
rejecting those that contain `invalid-argument-type` (those could not
possibly be solved by this PR) leaves 1281 diagnostics. The current
version of this PR removes 1171 diagnostics, which leaves 110
unaccounted for. I extracted the lint + file path for all of these
diagnostics and generated a diff (of diffs), to see which
`__init__`-diagnostics remain. I looked at a subset of these: There are
a lot of `SomeClass(*args)` calls where we don't understand the
unpacking yet (this is not even related to `__init__`). Some others are
related to `NamedTuple`, which we also don't support yet. And then there
are some errors related to `@attrs.define`-decorated classes, which
would probably require support for `dataclass_transform`, which I made
no attempt to include in this PR.

## Test Plan

New Markdown tests.

crates/red_knot_python_semantic/resources/mdtest/dataclasses.md

@@ -0,0 +1,242 @@
+# Dataclasses
+
+## Basic
+
+Decorating a class with `@dataclass` is a convenient way to add special methods such as `__init__`,
+`__repr__`, and `__eq__` to a class. The following example shows the basic usage of the `@dataclass`
+decorator. By default, only the three mentioned methods are generated.
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Person:
+    name: str
+    age: int | None = None
+
+alice1 = Person("Alice", 30)
+alice2 = Person(name="Alice", age=30)
+alice3 = Person(age=30, name="Alice")
+alice4 = Person("Alice", age=30)
+
+reveal_type(alice1)  # revealed: Person
+reveal_type(type(alice1))  # revealed: type[Person]
+
+reveal_type(alice1.name)  # revealed: str
+reveal_type(alice1.age)  # revealed: int | None
+
+reveal_type(repr(alice1))  # revealed: str
+
+reveal_type(alice1 == alice2)  # revealed: bool
+reveal_type(alice1 == "Alice")  # revealed: bool
+
+bob = Person("Bob")
+bob2 = Person("Bob", None)
+bob3 = Person(name="Bob")
+bob4 = Person(name="Bob", age=None)
+```
+
+The signature of the `__init__` method is generated based on the classes attributes. The following
+calls are not valid:
+
+```py
+# TODO: should be an error: too few arguments
+Person()
+
+# TODO: should be an error: too many arguments
+Person("Eve", 20, "too many arguments")
+
+# TODO: should be an error: wrong argument type
+Person("Eve", "string instead of int")
+
+# TODO: should be an error: wrong argument types
+Person(20, "Eve")
+```
+
+## `@dataclass` calls with arguments
+
+The `@dataclass` decorator can take several arguments to customize the existence of the generated
+methods. The following test makes sure that we still treat the class as a dataclass if (the default)
+arguments are passed in:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(init=True, repr=True, eq=True)
+class Person:
+    name: str
+    age: int | None = None
+
+alice = Person("Alice", 30)
+reveal_type(repr(alice))  # revealed: str
+reveal_type(alice == alice)  # revealed: bool
+```
+
+If `init` is set to `False`, no `__init__` method is generated:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(init=False)
+class C:
+    x: int
+
+C()  # Okay
+
+# error: [too-many-positional-arguments]
+C(1)
+
+repr(C())
+
+C() == C()
+```
+
+## Inheritance
+
+### Normal class inheriting from a dataclass
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Base:
+    x: int
+
+class Derived(Base): ...
+
+d = Derived(1)  # OK
+reveal_type(d.x)  # revealed: int
+```
+
+### Dataclass inheriting from normal class
+
+```py
+from dataclasses import dataclass
+
+class Base:
+    x: int = 1
+
+@dataclass
+class Derived(Base):
+    y: str
+
+d = Derived("a")
+
+# TODO: should be an error:
+Derived(1, "a")
+```
+
+### Dataclass inheriting from another dataclass
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Base:
+    x: int
+
+@dataclass
+class Derived(Base):
+    y: str
+
+d = Derived(1, "a")  # OK
+
+reveal_type(d.x)  # revealed: int
+reveal_type(d.y)  # revealed: str
+
+# TODO: should be an error:
+Derived("a")
+```
+
+## Generic dataclasses
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class DataWithDescription[T]:
+    data: T
+    description: str
+
+reveal_type(DataWithDescription[int])  # revealed: Literal[DataWithDescription[int]]
+
+d_int = DataWithDescription[int](1, "description")  # OK
+reveal_type(d_int.data)  # revealed: int
+reveal_type(d_int.description)  # revealed: str
+
+# TODO: should be an error: wrong argument type
+DataWithDescription[int](None, "description")
+```
+
+## Frozen instances
+
+To do
+
+## Descriptor-typed fields
+
+To do
+
+## `dataclasses.field`
+
+To do
+
+## Other special cases
+
+### `dataclasses.dataclass`
+
+We also understand dataclasses if they are decorated with the fully qualified name:
+
+```py
+import dataclasses
+
+@dataclasses.dataclass
+class C:
+    x: str
+
+# TODO: should show the proper signature
+reveal_type(C.__init__)  # revealed: (*args: Any, **kwargs: Any) -> None
+```
+
+### Dataclass with `init=False`
+
+To do
+
+### Dataclass with custom `__init__` method
+
+To do
+
+### Dataclass with `ClassVar`s
+
+To do
+
+### Using `dataclass` as a function
+
+To do
+
+## Internals
+
+The `dataclass` decorator returns the class itself. This means that the type of `Person` is `type`,
+and attributes like the MRO are unchanged:
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Person:
+    name: str
+    age: int | None = None
+
+reveal_type(type(Person))  # revealed: Literal[type]
+reveal_type(Person.__mro__)  # revealed: tuple[Literal[Person], Literal[object]]
+```
+
+The generated methods have the following signatures:
+
+```py
+# TODO: proper signature
+reveal_type(Person.__init__)  # revealed: (*args: Any, **kwargs: Any) -> None
+
+reveal_type(Person.__repr__)  # revealed: def __repr__(self) -> str
+
+reveal_type(Person.__eq__)  # revealed: def __eq__(self, value: object, /) -> bool
+```