docs(skills): teach the five-step locale ladder resolveLocaleAmong runs (#30700)

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_Requested by **Elon** · [project
thread](https://claude.ai/code/project/chan_01WedDzV26nniwxv7jC88B9D?thread=cmsg_01WedDzV26nniwxv7jC88B9DAi5Z7YR39qhBJcWtjJwHtT)_

Fixes #30603

Clause-②: no
Metadata-protocol: none

## 维护者速读

- 改了什么:`objectstack-i18n` 技能里讲内存兜底语言匹配顺序的那一句,从旧的四步改成代码实际跑的五步,并点名
`resolveLocaleAmong`,给出 `zh-TW` → `zh-Hant` 的例子。
- 为什么改:PR #30601 让两个服务端解析器共用
`resolveLocaleAmong`,在大小写不敏感和基础语言之间加了“平台语言表”一步;旧句子会让 AI 以为 `zh-TW`
落到第一个注册的 `zh-*`(可能是简体)。
- 风险与回滚:只改一句文档加一个 changeset,不动代码;回滚即 revert 本 PR。
- 先看:`skills/objectstack-i18n/SKILL.md` 第 376–379 行那一处 hunk。
- 两分钟验证:`node scripts/check-skills-token-ratchet.mjs | grep
objectstack-i18n/SKILL`,预期 5718 tokens(上限 6333,未抬上限)。
- 需要你做的:Tier H(`skills/**`),请在席位契约复核通过后审批合并。

## What changes

`skills/objectstack-i18n/SKILL.md`: the sentence on the in-memory
fallback's locale matching now names the ladder `resolveLocaleAmong`
(`@objectstack/spec/system`) runs, the one `resolveBundleLocale` also
runs, in the code's order: exact, case-insensitive, same platform-table
language (`zh-TW` → `zh-Hant`), base language, first registered variant.
One root changeset, `'@objectstack/skills': patch`. No other skill text
changes; no eval case added (the eval fixtures carry no locale-ladder
case, and the card scopes the sentence alone).

The five steps are read off `origin/main` `b77c160a`:
`packages/spec/src/system/i18n-resolver.ts` (`resolveLocaleAmong`, steps
1 to 5) and its test `resolveLocaleAmong answers the same over a list`
(`zh-TW` among `en, zh-CN, zh-Hant` answers `zh-Hant`); core's
`resolveLocale` in `packages/core/src/fallbacks/memory-i18n.ts` returns
`resolveLocaleAmong` directly.

## Tests

Docs-only diff under `skills/**`; no package code or test changes, so no
package test or typecheck owed.

## Acceptance notes

- Token readings (ceil(utf8 bytes / 4), release-stamp line excluded),
whole file: `skills/objectstack-i18n/SKILL.md` 5673 → 5718 tokens (+45),
ceiling 6333 unchanged, headroom 660 → 615. Lines 520 → 522; bytes 22712
→ 22891.
- Whole package: bundle total (whole shipped tree) 226234 → 226279
tokens (+45); all `SKILL.md` files summed 4534 → 4536 lines.
- The +45 is paid inside the existing ceiling's headroom; no ceiling
raised. The dispatch pins "no other skill text changes", so no same-file
deletion elsewhere in the skill was made.

## Verification

Every reading below is on head `d9c1c6b4` (base `origin/main`
`b77c160a`).

- `node scripts/pm/dispatch-gates.mjs --ran`: 44 derived families
accounted for, 44 run, 0 NOT-MEASURED, 0 UNRUN; every family exit 0.
- `pnpm lint`: exit 0.
- `node scripts/check-skills-token-ratchet.mjs`: exit 0;
`skills/objectstack-i18n/SKILL.md is 5718 tokens (ceiling 6333; headroom
615)`.
- `node scripts/check-commit-card-trailers.mjs --range
origin/main..HEAD`: exit 0.
- Five families first exited 3 (prerequisite: no dist):
`check:doc-formula-expressions`, `check:dts-closure`,
`check:dual-build-cjs-loads`, `check:lean-entry-closure`,
`check:sourcemap-no-sources-content`. After a whole-tree `turbo run
build` under `os-verify-lock.sh` (VERDICT command-exit 0), all five exit
0; those are the recorded codes.

<details><summary>Per-family exit codes</summary>

```text
node scripts/check-adr-0087-registration.mjs --base origin/main :: exit 0
node scripts/check-adr-0087-registration.mjs --self-test :: exit 0
node scripts/check-changeset-no-major.mjs --base origin/main :: exit 0
node scripts/check-closing-keyword-parity.mjs :: exit 0
node scripts/check-closing-keyword-parity.mjs --self-test :: exit 0
node scripts/check-comment-mask-corpus.mjs :: exit 0
node scripts/check-doc-route-spelling.mjs --advisory :: exit 0
node scripts/check-doc-route-spelling.mjs --self-test :: exit 0
node scripts/check-dts-emitted.mjs --self-test :: exit 0
node scripts/check-empty-changeset.mjs --base origin/main :: exit 0
node scripts/check-empty-changeset.mjs --self-test :: exit 0
node scripts/check-skills-token-ratchet.mjs :: exit 0
node scripts/check-skills-token-ratchet.mjs --self-test :: exit 0
node scripts/ci/assert-turbo-remote-cache.mjs --self-test :: exit 0
node scripts/ci/plan-test-core-shards.mjs --self-test :: exit 0
node scripts/ci/prune-turbo-cache.mjs --self-test :: exit 0
node scripts/pm/release-rehearsal-clone.mjs --self-test :: exit 0
node scripts/release-pending-publish.mjs --self-test :: exit 0
pnpm --filter @objectstack/spec run check:skill-docs :: exit 0
pnpm check:agent-test-spelling :: exit 0
pnpm check:changeset-gate-self-tests :: exit 0
pnpm check:ci-filter-parity :: exit 0
pnpm check:closed-ceremony-text :: exit 0
pnpm check:corpus-claim-drift :: exit 0
pnpm check:cross-package-test-inputs :: exit 0
pnpm check:doc-authoring :: exit 0
pnpm check:driver-memory-census :: exit 0
pnpm check:gitlink-declared :: exit 0
pnpm check:merge-driver :: exit 0
pnpm check:nul-bytes :: exit 0
pnpm check:pm-governed-merges :: exit 0
pnpm check:pm-skill-id-lint :: exit 0
pnpm check:published-files :: exit 0
pnpm check:refd-timer-probe :: exit 0
pnpm check:role-word :: exit 0
pnpm check:skill-compatibility :: exit 0
pnpm check:skill-frame-sync :: exit 0
pnpm check:skill-identifier-liveness :: exit 0
pnpm check:watch-hint-literal :: exit 0
pnpm --filter @objectstack/lint run check:doc-formula-expressions :: exit 0
pnpm check:dts-closure :: exit 0
pnpm check:dual-build-cjs-loads :: exit 0
pnpm check:lean-entry-closure :: exit 0
pnpm check:sourcemap-no-sources-content :: exit 0
pnpm lint :: exit 0
```

</details>

---
_Generated by [Claude
Code](https://claude.ai/code/session_016WV4czZcAEZpkY6CfBWJY7)_

Co-authored-by: Claude <noreply@anthropic.com>

Author: objectstack-fleet[bot]

.changeset/30603-i18n-skill-locale-ladder.md

@@ -0,0 +1,8 @@
+---
+'@objectstack/skills': patch
+---
+
+docs(skills): objectstack-i18n teaches the five-step locale ladder that `resolveLocaleAmong` runs (exact, case-insensitive, same platform-table language, base language, first registered variant), so a `zh-TW` request is taught to reach a registered `zh-Hant` bundle rather than the first `zh-*` one
+
+Clause-②: no
+Metadata-protocol: none

skills/objectstack-i18n/SKILL.md

@@ -373,8 +373,10 @@ registers when no i18n plugin is present):
   plugins can each contribute their own `objects.*` slice
 - **`getLocales()`** / **`setSupportedLocales()`** / **`getDefaultLocale()`** / **`setDefaultLocale()`**
 
-The in-memory fallback additionally resolves locale codes
-(exact → case-insensitive → base language `zh-CN` → `zh` → variant `zh` → `zh-CN`).
+The in-memory fallback additionally resolves locale codes through `resolveLocaleAmong`
+(`@objectstack/spec/system`), the one ladder `resolveBundleLocale` also runs: exact →
+case-insensitive → same platform-table language (`zh-TW` → `zh-Hant`) → base language
+`zh-CN` → `zh` → first registered variant `zh` → `zh-CN`.
 
 The contract also declares optional methods — `getFieldLabels`, `getCoverage`,
 `suggestTranslations` — that **no shipped implementation provides**. Treat them