feat(linkedin-studio): make long-form review language configurable [skip-docs]

Wave 3 / Step 9 of the remediation plan (Phase 1 — usable by a non-author).

The long-form review layer shipped Norwegian-locked: language-reviewer graded
unconditional Norwegian, voice-scrubber's gold standard was 'approved Norwegian
editions', and the editorial/content craft gates pointed at a 'skrivekontrakt §C2'
that does not ship. A non-Norwegian adopter would get English prose graded against
Norwegian idiom and a gate that depends on an unshipped contract.

- config/edition-state.template.json: add additive 'language' field (top-level,
  default 'en') + a _doc entry. Threads into the language-dependent agents.
- agents/language-reviewer.md: new 'Language parameter' section — Norwegian-specific
  checks (anglicism->Norwegian idiom, kanselli-stil) apply only when language=='no';
  any other value grades that language's equivalents and never flags idiomatic
  English as an anglicism. Default 'en'.
- agents/voice-scrubber.md: gold standard reframed to 'approved editions in the
  configured language'; the Norwegian-chronicle calibration is the language=='no'
  instantiation.
- agents/editorial-reviewer.md + agents/content-reviewer.md: the in-tree checklist
  is now the operative, self-contained source of truth; Maskinrommet §C2 is an
  optional upstream contract that does NOT ship (available only on the author's
  runs). The gates work for an adopter without it.
- commands/newsletter.md: thread 'language' through the Step 6.5 cold-inputs and the
  per-reviewer call inputs; the writing contract is now 'if it ships'.

Norwegian remains fully working when language: no (the author's case).

fact-reviewer.md was in the plan's file list but needed no change on inspection:
its F1-F4 checks (claims/quotes/numbers/sources) are language-agnostic; its
'Norwegian' mentions are boundary notes vs language-reviewer, which stay correct.

[skip-docs]: three-doc + version reconciliation is Step 21 (pre-review-gate); these
intermediate Wave commits are not pushed before the /trekreview gate.

Verify: edition-state JSON parses + has top-level language 'en'; language-reviewer
has 'language ==' references and no unconditional-Norwegian assertion; editorial
§C2 reframed to in-tree fallback ('operative source', 'does not ship'); agent
fixtures 35/35 pass; structural lint exit 0 (61 passed).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

plugins/linkedin-studio/agents/language-reviewer.md

@@ -38,6 +38,24 @@ You run at **Step 6.5** of the `/linkedin:newsletter` pipeline — *after* the
 in-session persona resonance sweep (Step 6), on a **frozen** draft, *before*
 lock — and you are invocable standalone via `/linkedin:headless-review`.
 
+## Language parameter — what language you grade against (configurable)
+
+You receive a **`language`** input from the edition-state
+(`config/edition-state.template.json`, default `"en"`). It tells you which
+language's rules to grade against — the review language is **not** hardcoded:
+
+- **`language == "no"` (Norwegian — the author's case):** the five
+  Norwegian-specific checks below apply in full — anglicisms flagged toward the
+  Norwegian idiom, «kanselli-stil», Norwegian clang/rhythm. This is the original
+  instantiation of the gate.
+- **`language: "en"` (default) or any other value:** apply the *equivalent* checks
+  for THAT language (calques into that language, that language's stiff/bureaucratic
+  register, that language's rhythm) and **never** grade the prose against Norwegian
+  idiom — do not flag idiomatic English as an "anglicism."
+
+If no `language` is supplied, assume `"en"`. Where the checks below say
+"Norwegian", read it as "the configured language" unless `language == "no"`.
+
 ## Pipeline position
 
 You are one of three **cold, headless re-readers** in the Step 6.5 package (with