docs+tests: locale Upgrading sections + flaky vector-supplement test fixes

[kevintseng]

Summary

Post-v4.2.7 cleanup that closes the two follow-ups noted in the v4.2.7 CHANGELOG.

Docs

• All 11 README locales now have an ## Upgrading section. EN + TH had it after v4.2.5; the other 9 (zh-TW, zh-CN, ja, ko, de, fr, es, pt, vi) were missing the section entirely. Heading parity across all locales is now 17/17.
• Every README gets a > [!IMPORTANT] "actively developed project" callout immediately after the hero divider, linking to GitHub Issues. Sets expectations that features evolve between releases and routes bug reports / feature requests to the right channel from the first glance.

Tests

Three flakes/environment-leaks fixed:

1. tests/transports/http.test.ts > returns array (possibly empty) for no-match query — asserted toHaveLength(0), but recallEnhanced may supplement FTS5 misses with sqlite-vec near-neighbours when ONNX embeddings are loaded. New assertion mirrors the actual API contract (valid JSON array, bounded length, entity-shaped rows).
2. tests/tools.test.ts > auto-archives entity when superseded by new remember — same root cause; recall('JWT') after archiving auth-v2 asserted exactly []. Behavioural guarantee is "archived rows stay hidden", so the assertion now checks not.toContain('auth-v2') instead of strict empty-array.
3. tests/hooks/pre-bash-orchestration-nudge.test.ts > emits nothing when MEMESH_ENABLE_AGENTIC_ORCHESTRATION is unset — the "default off" test deleted the env var but didn't pin MEMESH_DIR. On a developer machine with enableAgenticOrchestration: true in ~/.memesh/config.json, readHookConfig() reopened the gate and the test failed. Both the test helper and the gate-off case now point MEMESH_DIR at the per-test tmpdir.

Doc-sync checklist

• CHANGELOG.md updated (new [Unreleased] section)
• README.md + 10 locale READMEs synced (heading count: 17 across all)
• docs/ARCHITECTURE.md — no module/structure changes
• docs/api/API_REFERENCE.md — no public-surface changes
• CLAUDE.md — no project-structure changes
• Version files — not bumping; this is doc + test cleanup only
• dist/skills-manifest.json — no skills/hooks/plugin file changes

Test plan

• npm test -- --run tests/transports/http.test.ts tests/tools.test.ts tests/hooks/pre-bash-orchestration-nudge.test.ts — 83/83 pass
• npm test -- --run (full suite) — 65 files / 1045 tests pass
• Reviewer: verify CI is green before merge

[github-actions]

Multi-Model Synthesis

Both Claude and Codex reviews above are independent. The most
valuable signals are the issues only ONE model raised — those
are the blind spots single-model review misses.

Reviewer responsibility: read both, surface non-overlapping
findings, decide which need fixing before merge.