Simplify type aliases in shared_types.py

[TravisBumgarner]

Description

Refactor the type aliases in shared_types.py to use simpler syntax that displays better in IDEs.

Current Code

THandleOutOfBounds = Union[Literal["Warning"], Literal["Error"]]
TInstructionPhase = Union[Literal["setup"], Literal["plotting"], Literal["teardown"]]

Proposed Changes

HandleOutOfBounds = Literal["Warning", "Error"]
InstructionPhase = Literal["setup", "plotting", "teardown"]

Also add a Bounds TypedDict for the min/max point dictionaries:

class Bounds(TypedDict):
    x_min: float
    x_max: float  
    y_min: float
    y_max: float

Acceptance Criteria

• Type aliases use Literal["a", "b"] syntax instead of Union[Literal["a"], Literal["b"]]
• Remove the T prefix from type names (use HandleOutOfBounds not THandleOutOfBounds)
• Add Bounds TypedDict for structured return types
• Update all imports throughout the codebase to use new names
• All existing tests pass
• mypy passes with no new errors