fix(providers): keep compatibility rules and metadata adapter owned

[anycodes]

Description

Merged isolation code still formatted native envd URLs in core compatibility helpers, bypassing an adapter-owned rule. Pure Express configuration data lives in the provider; a separate distribution composition supplies neutral configuration through compatibility exports. Historical URL helpers call the composed provider-owned builder. Neutral imports still load no native authentication/runtime adapter.

Fixes #66. Counterpart: Alibaba-Agent-Sandbox/agent-sandbox#61. Original isolation PR is already merged; this follow-up completes its metadata/rule ownership boundary.

Type of Change

• Bug fix
• Refactoring
• Tests
• Documentation

Changes

• Keep backend defaults and URL conventions in provider-owned data/adapters, with explicit distribution composition and compatibility exports.
• Add an opaque-rule regression; the same negative controls fail on unchanged merged main and pass with this implementation.
• Preserve accepted auth/native HTTP contracts, public aliases, cleanup behavior and independent production wheel/auth-preflight repairs.
• Include English/Chinese boundary docs, implemented ADR, immutable acceptance records and capture evidence. The existing Unreleased provider-isolation CHANGELOG entry already describes this completion.

Testing

Latest-head Python3.10/3.11/3.12 client/server matrices, package builds, hygiene and Markdown links all pass. Local full client2178 passed/24 skipped, then the9-pass isolation file covers the appended owned-builder regression. Both-package ruff/format/mypy and combined clean wheel imports pass. The disclosed local malformed HTTP intermediary failures remain separate; their unchanged assertions pass in hosted server jobs.

Real merged-source Express smoke:58 passed,1 known Jupyter xfail,1 throughput-dependent non-strict xpass. Current executable cloud/management cases pass with2 owned sandboxes deleted and zero leaked; corrected offline rerun61 passed/1 no-resource skip. Earlier116-pass full E2E and fresh OSS persistence2-pass/binary mount2-pass runs remain at their recorded implementation revisions. Temporary key/Volume/Bucket/policy/role deletion and independent zero-sandbox listing are verified.

Health/hygiene and configured-secret scans pass. Details: .agents/evidence/verify/2026-10-18-provider-owned-metadata-followup.md, plus its linked convergence and real-storage records.

Checklist

• Code, contracts and historical exports preserved
• Unit regressions and latest-head hosted CI pass
• Real Express behavior and cleanup recorded
• Bilingual docs, implemented ADR, CHANGELOG context and evidence
• Repository health/hygiene pass; no secrets included

Definition of Done

• Required current-head CI and mergeability verified
• Regression, real-component and package evidence included
• Docs and engineering records complete for this scoped repair

Native E2B/Cube/container/OpenSandbox environment acceptance and the separately gated image-factory contract are outside this repair; no new native coverage or package release is claimed.

Post-merge verification: merged as 5a99f0fa294d1b801e1006981d2af87e3a486507; the exact main-branch CI matrix also passed all configured jobs. The linked owner Issue #66 is closed. No package publication is implied.