chore: major type fixes

[erhant]

• Added a shard/attrib.py to shard to share types of attributes / methods among mixins, fixing around 196 type errors under shard folder.
• Moved some shard/startup.py methods to shard/node.py, and moved some from both to a new shard/comms.py mixin that is a renewed form of shard/send.py mixin. It basically handles communication related functions.
• Fixed some class fields that have Field(default=...) but is still Optional to be their designated types.
• Fixed a variety of: type mismatches, misconfigured object instantiations, unnecessary getattr statements.
• Added a few fixes to api/node.py as well.
• Added # FIXME comments to several places.
• Added VsCode tasks for ease of testing, along with testing docs & Make rule.

Resolves #7

Copilot Summary

This pull request introduces several improvements and fixes to the development workflow, API parameter handling, and server logic. The most significant changes include adding VSCode tasks for common development actions, refining how API parameters are handled and validated, and improving the robustness and clarity of the API server's internal logic.

Development workflow enhancements:

• Added a .vscode/tasks.json file with pre-configured tasks for starting API and shard servers, running health checks, preparing and loading models, and making test API calls, making it easier to develop and test locally in VSCode. Also updated .vscode/.gitignore to only track relevant files. [1] [2]
• Updated the README.md with instructions for running tests and using the new VSCode tasks, making onboarding and local development more accessible.
• Added a test target to the Makefile for running tests with pytest, and updated the pyproject.toml to use the correct test file pattern. [1] [2]

API parameter and model validation improvements:

• Refactored ChatParams in models.py to use non-optional types with default values, improving type safety and ensuring default values are always set. Also standardized the stop parameter handling.

API server logic and robustness fixes:

• Improved error handling and logging throughout node.py, including clearer error messages and more robust topology/device checks. [1] [2]
• Refactored model and topology selection logic in _handle_load_model, ensuring correct model assignment and fallback behavior, and simplified device/shard mapping. [1] [2] [3] [4] [5]
• Cleaned up and clarified type annotations and usage in several endpoints and internal functions, including handling of streaming responses and device assignments. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]

These changes collectively improve developer experience, code quality, and the reliability of the API server.

[andthattoo]

got through the changes w/ erhant