[codex] add SDK guides

[k82cn]

Summary

• Add central SDK documentation for Rust and Python under docs/sdk/.
• Add a task-oriented Rust API tutorial based on the existing Rust Pi example.
• Link the new docs from the README, API docs, Runner setup guide, and SDK-local READMEs.
• Add a Rust SDK README and update the flame-rs package metadata to use it.
• Align the Python SDK README requirement with package metadata by documenting Python >=3.9.

Validation

• git diff --check
• local Markdown link check for touched docs
• cargo check -p flame-rs --all-targets --features macros
• python3 -m compileall -q sdk/python/src/flamepy
• cargo check -p pi --all-targets

fixes #47

[gemini-code-assist]

Code Review

This pull request significantly expands the project's documentation by adding a general SDK overview, dedicated guides for the Python and Rust SDKs, and a comprehensive Rust API tutorial. It also updates various README files and existing tutorials with relevant links and corrects the Python version requirement. Feedback on the new Rust API tutorial points out a likely compilation error where try_join_all is used on task handles; the reviewer suggests using join_all instead because the underlying futures resolve to a result struct rather than a standard Result type.

[gemini-code-assist]

The use of try_join_all on handles is likely incorrect here. According to the SDK documentation in docs/sdk/rust.md (line 93) and the description later in this tutorial (line 131), TaskFuture resolves to a TaskResult struct which contains metadata and error details, rather than a standard Rust Result.

try_join_all is designed for futures that return Result<T, E> and will fail fast if any future returns Err. If TaskFuture resolves to a struct, try_join_all will not compile. You should use join_all instead to wait for all tasks to complete and then inspect the TaskResult objects.

Additionally, ensure that join_all (and try_join_all if used for submission) are imported from the futures::future module.

Suggested change

	let handles =
	try_join_all((0..cli.task_num).map(|_| ssn.run::<_, PiResponse>(&request))).await?;
	let tasks = try_join_all(handles).await?;
	let handles =
	try_join_all((0..cli.task_num).map(|_| ssn.run::<_, PiResponse>(&request))).await?;
	let tasks = join_all(handles).await;

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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