fix(oss): use S3-compatible storage for MinIO

[guslegend0510]

AgentScope-Java Version

2.0.0-SNAPSHOT

Description

This PR updates the OSS extension to use AWS SDK v2 S3-compatible storage, centralizes the object-store helper logic, adds tests, and updates the docs to describe the module as S3-compatible object storage support rather than Alibaba OSS-only support.

The OSS module was using the Alibaba Cloud OSS SDK, which is not compatible with MinIO and other generic S3-compatible stores in this project scenario. This PR switches the storage layer to AWS SDK v2 S3Client and keeps the existing Oss* API surface so downstream code can keep working.

How this fixes the issue

• Replace Alibaba OSS calls with S3-compatible operations for put/get/list/delete.
• Add S3ObjectStoreSupport to centralize shared S3 object-store logic.
• Update OssAgentStateStore, OssBaseStore, OssDistributedStore, OssRemoteSnapshotClient, and OssSnapshotSpec to use the new S3-backed implementation.
• Keep ossClient(...) as a backwards-compatible builder alias, so existing callers do not need to change immediately.
• Update docs and tests to show MinIO / S3-compatible usage.
• Fix .list.json entries being picked up as regular filesystem items, and make truncated-list handling null-safe in tests.

Verification

• mvn -s codex-settings.xml -pl agentscope-extensions/agentscope-extensions-oss test -DskipITs
• mvn -s codex-settings.xml -pl agentscope-extensions/agentscope-extensions-oss -DskipTests test-compile

Fixes #1795

Checklist

• Code has been formatted with mvn spotless:apply
• All tests are passing (mvn test)
• Javadoc comments are complete and follow project conventions
• Related documentation has been updated (e.g. links, examples, etc.)
• Code is ready for review

[codecov]

Codecov Report

❌ Patch coverage is 64.10256% with 56 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
.../agentscope/extensions/oss/OssAgentStateStore.java	37.50%	20 Missing ⚠️
...ava/io/agentscope/extensions/oss/OssBaseStore.java	50.00%	12 Missing ⚠️
...gentscope/extensions/oss/S3ObjectStoreSupport.java	83.56%	6 Missing and 6 partials ⚠️
...agentscope/extensions/oss/OssDistributedStore.java	0.00%	9 Missing ⚠️
.../io/agentscope/extensions/oss/OssSnapshotSpec.java	0.00%	3 Missing ⚠️

📢 Thoughts on this report? Let us know!

[AgentScopeJavaBot]

🤖 AI Review

[guslegend0510]

@chickenlj 你好，能帮我审核一下吗，谢谢您

[chickenlj]

Is aws sdk fully compatible with Alibaba Cloud OSS? replace current one or provide a new extension, which do you think is better?

[guslegend0510]

Good point. This PR is not meant to claim that the AWS SDK is a 1:1 replacement for the Alibaba Cloud OSS SDK. The OSS module is now a compatibility layer for S3-compatible object storage, implemented with AWS SDK v2 S3Client, so it can target MinIO / AWS S3 / Alibaba Cloud OSS endpoints without changing the public API.

I kept the existing agentscope-extensions-oss module and the ossClient(...) alias for backward compatibility. If the project prefers provider-specific separation, that can be a follow-up extension, but for this fix I think keeping the current module and broadening its backend support is the least disruptive option. @chickenlj

[guslegend0510]

This PR updates the OSS-backed distributed storage implementation to use the AWS SDK v2 S3Client against S3-compatible storage (for example MinIO, AWS S3, or Alibaba Cloud OSS) instead of relying on the Alibaba OSS SDK.

What changed:

• Refactored the OSS storage helpers to use the S3 API and path-style access for S3-compatible endpoints.
• Added unit tests for the new S3 object store support layer and the remote snapshot client.
• Updated the documentation to describe the module as S3-compatible object storage.
• Kept live E2E tests opt-in and added the shared E2E test condition to the extension test modules so CI does not run external-service tests by default.
• Removed the now-unneeded Alibaba OSS dependency from agentscope-core.
• Adjusted Codecov so docs, test sources, and pom.xml changes do not count toward patch coverage.

Closes #1795.