fix(sandbox): pause and reuse OpenSandbox resources

[DigHuang]

What changed

• change OpenSandboxAdapter.stop() from deleting the remote sandbox to pausing it and wait for the asynchronous Pausing -> Paused transition
• preserve metadata-based remote reuse and reuse an already-bound running SDK client without reconnecting
• align lifecycle, readiness, endpoint cache invalidation, transport cleanup, and command output handling with OpenSandbox SDK 0.1.10
• allow paused sandbox info lookup without connecting to execd
• consolidate deterministic OpenSandbox adapter tests and restore the stop/start integration contract

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	18.37%	1629 / 8865
🔵	Statements	18.36%	1710 / 9310
🔵	Functions	16.12%	340 / 2108
🔵	Branches	15.12%	761 / 5032

File Coverage

No changed files found.

Generated in workflow #1664 for commit ab2d077 by the Vitest Coverage Report Action

[github-actions]

✅ Admin Preview Image Ready!

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🕒 Time: 2026-07-23 17:41:00 (UTC+8)

[github-actions]

✅ Build Successful - Preview fastgpt Image for this PR:

ghcr.io/labring/fastgpt-pr:fastgpt_ab2d0775fde8573b0ea6e18710d4a9a0c6d49f61

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