feat(storage): orchestrate resumable uploads

[swkeever]

Summary:

• add upload_resumable for byte payloads
• honor the server-selected part size
• abort best-effort after part failures without masking the original error
• document the high-level flow

Scope:
Facade-only composition of existing resumable upload operations. No OpenAPI or Hosting behavior changes.

Verification:

• OpenAPI provenance check
• Ruff and formatting
• mypy and Pyright
• 257 unit tests
• Behave contract dry run
• package build
• Hosting SDK contract guards

[swkeever]

@codex review

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-02T16:23:12.826834Z	36e198f	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Already looking forward to the next diff.

Reviewed commit: 36e198ff15

ℹ️ About Codex in GitHub

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• Comment "@codex review".

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