docs: bilingual docs contract, translation skill, and pairing gate

Establish EN->ZH bilingual documentation for the README and docs tree:

- docs/i18n/README.md — the pairing contract: sibling foo.md <-> foo.zh.md,
  English canonical, blob-hash source fingerprints, language switchers,
  scope/exclusions, and a manifest-driven rollout ratchet.
- docs/i18n/translation-rules.md — how to translate: faithfulness, structure
  preservation, terminology discipline over docs/i18n/terminology.md, and
  typography rules grounded in MDN/K8s/Vue/clreq conventions.
- .agents/skills/dsh-translate-docs — the committed agent workflow, following
  the dsh-code-review pattern of deferring to docs as sources of truth.
- scripts/verify-translation-pairing.ts + manifest — a doc-sync gate: required
  pairs exist; every existing .zh.md is fresh (fingerprint = current source
  blob), switcher-linked, structure-matched, and non-orphaned; excluded
  (generated) docs stay unpaired. --list prints the translation work list.
- RFC (implemented/process) recording the decision and the alternatives.
- Dogfood: README.zh.md and the two i18n docs translated under their own rules.

Gates: doc-sync green including the new gate; red/green proven for stale
fingerprint, orphan, and excluded-file violations.

.agents/skills/dsh-code-review/SKILL.md

@@ -34,7 +34,7 @@ These come straight from the source docs above. They are not discretionary; abse
 1. **Docs in sync.** If the PR changes a config key, default, error code, wire field, or event name, it must update the package README + module/JSDoc in the same diff. The `doc-sync` gate (check #4) does not catch prose drift in config keys, defaults, error codes, or wire fields — that is on the reviewer, but it is still required, not optional.
 2. **Core-data-structures catalog in sync.** If the PR adds, removes, or reshapes a type the [core-data-structures catalog](../../../docs/core-data-structures/core.md) documents — a new `…Map` variant, a new content-block/session-event type, a field on `GenerateOptions`/`Agent`/`ToolDefinition`/a bash type, or a whole new core/seam type — it must update that catalog in the same diff (prose + any verbatim ` ```ts type-equiv ` block + the 1:1 `scripts/type-equiv.manifest.json`). The `verify-type-equiv` gate (part of `doc-sync`) catches a *drifted paste* of an already-documented type, but it cannot tell you a brand-new core type went undocumented — that judgment is yours. Confirm a genuinely spine-level type landed in core.md and a new capability's vocabulary on a sub-page, per the spine-vs-seam line in [core.md § What counts as "core"](../../../docs/core-data-structures/core.md#what-counts-as-core). A pure internal type with no cross-package reach needs no catalog entry — say so if it's a judgment call.
 3. **HMR-safety test.** Any new registry/registration needs a test that disposes the contributing fiber and asserts cleanup (packages/AGENTS.md). Its absence blocks merge.
-4. **Quality gates pass.** typecheck, lint, test, test:coverage (100% per-file on `packages/*/src`), knip, build, publint, constraints, `doc-sync` (doc-typecheck + verify-cordis-catalog + verify-md-wrap + verify-md-links + verify-type-equiv), module-graph freshness (the quality-gates RFC). Don't re-review what a gate already enforces — trust the gate and spend attention on what it can't check. Note that the `doc-sync` gate only covers compilable `ts` blocks, the generated cordis events/services catalog, markdown wrapping/links, and verbatim type-equiv blocks; prose drift (checks #1 and #2) is *additional* manual review on top of it, not covered by it.
+4. **Quality gates pass.** typecheck, lint, test, test:coverage (100% per-file on `packages/*/src`), knip, build, publint, constraints, `doc-sync` (doc-typecheck + verify-cordis-catalog + verify-md-wrap + verify-md-links + verify-type-equiv + verify-translation-pairing), module-graph freshness (the quality-gates RFC). Don't re-review what a gate already enforces — trust the gate and spend attention on what it can't check. Note that the `doc-sync` gate only covers compilable `ts` blocks, the generated cordis events/services catalog, markdown wrapping/links, verbatim type-equiv blocks, and the bilingual pairing contract ([docs/i18n/README.md](../../../docs/i18n/README.md)); prose drift (checks #1 and #2) and translation *quality* (the [dsh-translate-docs](../dsh-translate-docs/SKILL.md) rules) are *additional* manual review on top of it, not covered by it.
 
 ## Reviewer-only checks (gates can't catch these — judgment required)