chore(master): release synapse-core 0.3.1

[github-actions]

📦 Release Preparation

0.3.1 (2026-03-17)

Features

• new usdfc dataset sybil fee (#666) (f1bfc44)

Bug Fixes

• pieceStatus confuses piece ownership. Closes #296 (#655) (be76ad1)
• support multi sp upload flow in react and demo (#675) (7f70914)

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🚀 How to Release

1. Review the changelog and version bump in this PR
2. Merge this PR to trigger the release
3. After merging, the workflow will:
   • Create a GitHub release with tag ${version}
   • Publish to npm automatically
4. Wait until the workflow is complete before merging another release PR

⚠️ Note: The release has NOT been created yet. It will only be created after you merge this PR.

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	synapse-dev	42f4a2e	Commit Preview URL Branch Preview URL	Mar 17 2026, 02:42 PM

[github-actions]

🤖 Created releases:

• synapse-core-v0.3.1

🌻