fix: publish local plugin release notes in English

[MLittleprince]

Summary

• render the visible MemOS local-plugin GitHub Release changelog in English
• keep the hidden bilingual Doc Agent payload, source_refs, and CN/EN docs previews unchanged
• normalize manually supplied stable notes through the same English public rendering path

This is a focused follow-up to merged PR #2249. Both the standalone stable publisher and the paired weekly publisher use this shared generator. Prerelease package-only behavior is unchanged.

Verification

• 155 local-plugin release and MemOS paired-release tests passed
• verified public Release categories contain no CJK while CN docs categories retain Chinese
• git diff --check passed
• sensitive-value scan passed

Historical releases

This fixes future Releases only. Existing v2.0.16 and v2.0.17 docs gaps require controlled webhook recovery after their historical evidence is checked; this PR does not redeliver webhooks or publish anything.

[Memtensor-AI]

🤖 Open Code Review

Target: PR #2296
Task: db808bc92c6c7df0
Base: main
Head: fix/local-plugin-release-english

✅ OpenCodeReview: Review complete: 0 finding(s) across 2 selected item(s).

Generated by cloud-assistant via Open Code Review.

[Memtensor-AI]

✅ Automated Test Results: PASSED

All tests passed (1/1 executed). memos_github_open_source/smoke: 1/1. Duration: 1s

Branch: fix/local-plugin-release-english

[Memtensor-AI]

✅ Automated Test Results: PASSED

All tests passed (1/1 executed). memos_github_open_source/smoke: 1/1. Duration: 1s

Branch: fix/local-plugin-release-english

[Memtensor-AI]

✅ Automated Test Results: PASSED

All tests passed (1/1 executed). memos_github_open_source/smoke: 1/1. Duration: 1s

Branch: fix/local-plugin-release-english