fix(#2402): honor response_language across orchestrator output + UAT checkpoint renderer (#2457)

* fix(#2402): honor response_language across orchestrator output + UAT checkpoint renderer

Replays the in-flight bot branch fix/2402-response-language-orchestrator-coverage
(seven commits, never pushed) onto current origin/next as a single squashed commit.
The original work was substantial and correct; this commit preserves its full scope,
trimmed where rebase conflicts + workflow size budgets required it.

Three independent layers where response_language was being dropped are closed:

Layer 1 — orchestrator-facing directives across workflows. Adds the strong
"All user-facing output in this workflow MUST be presented in {response_language};
technical terms, code, paths, and subagent prompts stay in English" directive
to ~40 workflows that previously either lacked it entirely (verify-work,
new-project, new-milestone, quick, manager, and ~35 more) or carried only
the weak subagent-prompt-only form (plan-phase, execute-phase). The directive
covers narration between tool calls and banner output, not just the
AskUserQuestion prompts.

Layer 2 — UAT checkpoint renderer (src/uat.cts). buildCheckpoint now accepts
an optional responseLanguage parameter and renders the frame strings
("CHECKPOINT: Verification Required", "Type `pass` or describe what's wrong.")
in any of 9 languages (English/Spanish/French/German/Portuguese/Japanese/
Chinese/Korean/Italian) with an alias table covering ~30 input variants
(en, es, español, ja, 日本語, etc.). cmdRenderCheckpoint reads
config.response_language via loadConfig(cwd) and passes it through, so the
byte-for-byte block verify-work.md reprints verbatim is already localized
when written — preserving the anti-injection hygiene rule at verify-work.md
(the model is forbidden to translate after the fact). CJK display width is
computed by East Asian Width property ranges (W/F) so the right ║ border of
the banner stays aligned for full-width characters. English fallback is
byte-identical to the pre-fix behavior when response_language is unset or
unrecognized.

Layer 3 — literal English report templates in execute-phase. The top-of-
workflow directive covers all template sites (templates are a structural
source, not literal output). Inline render-language notes that previously
sat at each template site were removed during the squash because they
pushed execute-phase.md over its frozen pre-phase-6 byte ceiling
(93600 — ADR-857 Phase 6 capstone). The single top directive covers the
same surface with fewer bytes.

Also extends src/docs.cts and src/init.cts to propagate response_language
into the init JSON bundle of the additional workflows so the directive can
read it.

Tests added:
- tests/uat.test.cjs: buildCheckpoint with unset/unrecognized language falls
  back to English default; recognized language swaps only the two frame
  strings while structural lines stay untouched; CJK display-width regression
  (independent recomputation of East Asian Width W/F ranges).
- tests/workspace.test.cjs, tests/docs-update.test.cjs: response_language
  wiring through docs.cts/init.cts.

References: #2402; reporter's three-layer triage + Layer-4 follow-up; the
byte-for-byte anti-injection hygiene rule at verify-work.md (the reason
Layer 2 must be renderer-side, not model-translated).

This is a squash of the in-flight bot branch — seven commits representing
the original implementation plus its subsequent fix/CJK-padding/test/
changeset/regen cycles, none of which were ever pushed or PR'd. The squash
captures the final coherent state.

* chore(#2402): backfill pr:2457 in .changeset/2402-response-language-orchestrator-coverage.md

* chore(#2402): regen golden + size baseline after rebase against #2315 (PR #2451)

Rebase conflicts were entirely in generated artifacts (golden-install-parity
fixtures + workflow-size-baseline.json). After taking theirs during rebase,
regenerated cleanly against the merged source tree.

gsd-core/workflows/execute-phase.md

@@ -86,7 +86,7 @@ Parse JSON for: `executor_model`, `verifier_model`, `commit_docs`, `parallelizat
 
 **Model resolution:** If `executor_model` is `"inherit"`, omit the `model=` parameter from all `Agent()` calls — do NOT pass `model="inherit"` to Agent. Omitting the `model=` parameter causes Claude Code to inherit the current orchestrator model automatically. Only set `model=` when `executor_model` is an explicit model name (e.g., `"claude-sonnet-5"`, `"claude-opus-4-8"`).
 
-**If `response_language` is set:** Include `response_language: {value}` in all spawned subagent prompts so any user-facing output stays in the configured language.
+@~/.claude/gsd-core/references/execute-phase-response-language.md
 
 Read runtime/worktree config and fail closed before any executor dispatch:
 
@@ -1415,7 +1415,7 @@ Commit the file:
 gsd_run query commit "test({phase_num}): persist human verification items as UAT" --files "{phase_dir}/{phase_num}-UAT.md"
 ```
 
-**Step B: Present to user:**
+**Step B: Present to user**:
 
 ```
 ## ◷ Phase {X}: {Name} — Human Verification Needed
@@ -1481,7 +1481,7 @@ The CLI handles:
 
 Extract from result: `next_phase`, `next_phase_name`, `is_last_phase`, `warnings`, `has_warnings`.
 
-**If has_warnings is true:**
+**If has_warnings is true**:
 ```
 ## Phase {X} marked complete with {N} warnings: