[anycodes]

Description

Lead with Python use cases, installation and one interpreter example with deletion in finally. Explain Sandbox, AsyncSandbox, code_interpreter and ProviderSandbox in a small selection table. Link provider/template, server, authentication and migration guides. Keep client/server package ownership visible without namespace implementation details.

Requested as a review and improvement of all eight repository READMEs. This PR covers only python-sdk. Migration and maintenance details remain available through their owning guides. No runtime code or public API changes.

Type of Change

• Documentation

Changes

• Rewrite the repository entry point for its primary audience and provide matching English/Chinese navigation.
• Keep detailed reference or maintainer material in its appropriate guide.
• Add the owning repository decision and dated verification record.

Testing

• Changed Markdown links/anchors, language navigation and Python snippet syntax: pass.
• Scoped diff and translation review: pass.
• bash scripts/check-repo-health.sh: PASS: 106 checks, 0 failures; 1 warning.
• make hygiene: PASS.
• make test: PARTIAL: server suite 872 passed, 1 skipped, 3 failed; make stopped before client suite.
• pytest (three failed server tests after installing missing pip in the test environment): PARTIAL: package-list test now passes; malformed WebSocket and chunked-request tests still receive HTTP 501/502 instead of 400.
• pytest tests/ (client-sdk): PASS: 2348 passed, 27 skipped.
• make lint typecheck: PASS: Ruff checks passed for both packages; mypy passed for 56 server and 101 client source files (one unused-section configuration note).

Checklist

• English and Chinese documentation updated
• Repository-owned note and verification included
• No secrets or unrelated changes included
• Existing licenses and attribution preserved

Definition of Done

Documentation-only scope. Existing cloud/model acceptance receipts are preserved; no new runtime, model, cloud deployment or package-release claim is made. Runtime/template-specific checklist items are not applicable. Required latest-head CI and review gates remain in effect.

Local server follow-up: after installing missing pip in the isolated test environment, the package-list case passes. Two malformed raw-HTTP cases still return 501/502 rather than 400; their reason is not established and source is unchanged. The full latest-head remote matrix remains a merge gate.