chore(ci): use in-built downloader instead of aria2c

[LesnyRumcajs]

Summary of changes

#6632 roughly matches aria2c performance (or at least, it should) so no need to do it manually.

Changes introduced in this pull request:

• use in-built downloader in scripted tests instead of aria2c

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Outside contributions

• I have read and agree to the CONTRIBUTING document.
• I have read and agree to the AI Policy document. I understand that failure to comply with the guidelines will lead to rejection of the pull request.

Summary by CodeRabbit

• Chores
  • Removed automatic snapshot download behavior from test scripts and CI configuration, disabling the prior auto-download pathway.
  • Test startup now launches nodes directly, simplifying initialization and keeping other test behaviors unchanged.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between bf27bfc and 462ae20.

📒 Files selected for processing (1)

• .github/workflows/forest.yml

💤 Files with no reviewable changes (1)

• .github/workflows/forest.yml

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Walkthrough

Removed the automatic snapshot download handler and its invocations across test scripts and CI workflow, disabling the FOREST_AUTO_DOWNLOAD_SNAPSHOT_PATH-based auto-download pathway.

Changes

Cohort / File(s)	Summary
Calibnet Check Scripts scripts/tests/calibnet_kademlia_check.sh, scripts/tests/calibnet_no_discovery_check.sh, scripts/tests/calibnet_stateless_mode_check.sh	Removed calls to handle_auto_download_snapshot_env before starting the node; node startup and subsequent logic unchanged.
Test Harness scripts/tests/harness.sh	Removed handle_auto_download_snapshot_env function and its invocation; removed conditional logic around FOREST_AUTO_DOWNLOAD_SNAPSHOT_PATH in forest_download_and_import_snapshot.
CI Workflow .github/workflows/forest.yml	Removed FOREST_AUTO_DOWNLOAD_SNAPSHOT_PATH from workflow environment variables.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• fix(ci): speed up snapshot downloading on CI #6592 — Reverts/adds the handle_auto_download_snapshot_env function and its invocations (directly related).
• fix(links): update the script to use latest calibnet snapshot #6117 — Related changes to snapshot download handling in test/CI scripts.

Suggested reviewers

• sudo-shashank
• akaladarshi

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: replacing aria2c with the project's built-in downloader in CI scripts. It accurately reflects the primary objective of the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch use-in-built-downloader

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