Move fully-async rollout from examples into miles/rollout

[yueming-yuan]

Motivation

Fully-async rollout is used by production runs (the swe-agent-v2 GLM-4.7 async scripts) but its implementation lives in examples/fully_async/, wired up via a PYTHONPATH hack in every launch script. Core arguments it consumes (--max-weight-staleness) are already defined in core arguments.py while their only consumer sits in examples. First step of moving it into the core library.

What this PR does

Pure mechanical move — no logic changes:

• git mv examples/fully_async/fully_async_rollout.py → miles/rollout/fully_async_rollout.py (100% rename similarity; blame/history preserved).
• All references switch to --rollout-function-path miles.rollout.fully_async_rollout.generate_rollout_fully_async and the example-dir PYTHONPATH entries are removed: the two qwen launch scripts, the two swe-agent-v2 async scripts (FULLY_ASYNC_DIR hack deleted), and the docs pages that referenced the old path.
• examples/fully_async/ keeps the launch scripts + README, now pointing at the core module.

A follow-up PR (stacked) rewrites the module on the class-based rollout API.

Testing

Pure rename + path updates; pre-commit run --all-files passes. The moved module is import-compatible (same content, same imports).

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request moves the fully_async_rollout.py module from the examples directory to the core library at miles/rollout/fully_async_rollout.py, updating all corresponding documentation, scripts, and launch configurations. The reviewer identified a potential ModuleNotFoundError in run_qwen3_30b_a3b_fully_async.py due to the omission of the repository root from PYTHONPATH after removing the local directory, and provided a code suggestion to resolve it.

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[gemini-code-assist]

Omitting the repository root (U.repo_base_dir) from PYTHONPATH can lead to a ModuleNotFoundError when attempting to import miles (such as miles.rollout.fully_async_rollout) if the script is executed from a different directory or in environments where the package is not installed globally. Adding U.repo_base_dir to PYTHONPATH ensures consistency with other launch scripts and prevents potential import issues.

Suggested change

	extra_env_vars={
	"FLASHINFER_DISABLE_VERSION_CHECK": "1",
	"PYTHONPATH": f"{args.megatron_path}:{fully_async_dir}",
	"PYTHONPATH": args.megatron_path,
	},
	)
	extra_env_vars={
	"FLASHINFER_DISABLE_VERSION_CHECK": "1",
	"PYTHONPATH": f"{args.megatron_path}:{U.repo_base_dir}",
	},
	)

[guapisolo]

I suggest we directly add a args --fully-async to make sure all user know there is a fully async example.

[guapisolo]

Also we need to add a fully async CI on dapo math, will submit a PR later.

[guapisolo]

I suggest we directly add a args --fully-async to make sure all user know there is a fully async example.

I am let codex doing this.

[guapisolo]

Submitted to #1924 stack on #1782 to avoid cascade rebase

[guapisolo]

Handle fully async flag name in later PR. So approve this as-is.