[anycodes]

Description

The READMEs embedded in Python distributions still sent users to 0.3.1a2 and described publication as pending. Correct those commands, lead the bilingual installation guide with the current public-package recipe, and move maintainer publication mechanics out of the user installation flow.

Refs #101 and #99. The a4 publication was stopped before any upload step; its tag remains unchanged. Matching a5 distributions carry the corrected descriptions and the same application runtime.

Type of Change

• Documentation
• Packaging

Changes

• Package/root READMEs use explicit alpha opt-in without a stale version pin; the bilingual guide provides the fixed a5 installation.
• Keep client/server version and required dependency in lockstep.
• Retain checkout-based development instructions and put publication requirements in CONTRIBUTING.
• Record the intentionally cancelled a4 upload separately from successful validation.

Testing

• 14 package/release regressions passed.
• make build dist-check passed, including both wheel/sdist pairs and clean combined installation.
• Actual wheel metadata and sdist README inspection passed for both packages; exact client/server a5 dependency confirmed.
• Health check: 106 PASS, 1 existing warning, 0 failures; diff check passed.
• Full current-head CI and Markdown links passed: https://github.com/Alibaba-Agent-Sandbox/python-sdk/actions/runs/40112563463 and https://github.com/Alibaba-Agent-Sandbox/python-sdk/actions/runs/40112563366.

Checklist / Definition of Done

• Bilingual documentation, changelog and per-repository decision/evidence files included.
• No runtime behavior change; existing real proxy acceptance and independent cleanup remain applicable: https://github.com/Alibaba-Agent-Sandbox/awesome-providers/actions/runs/40110372103.
• No credentials, private IDs or raw logs included.
• Public a5 distribution readback and fresh installation will be recorded after release; keep Issues docs: correct installation instructions shipped in Python package metadata #101/fix: preserve application token authentication through filtering proxies #99 open until then.