feat(views): localize generated-view chrome via the manifest anchor language

[takashi-matsuyama]

Summary

The generated views (handoff.md / orientation.md / decisions.md / basou report generate) hardcoded Japanese section headings and verdict prose — contradicting the English-first OSS positioning (the mismatch surfaced concretely while drafting the English tutorial that walks readers through basou handoff generate). This PR localizes the tool-generated chrome per workspace, driven by the manifest declaration:

The workspace speaks the anchor's language. The view language resolves from the repos[] entry whose path is .:

• anchor language: ja → Japanese chrome (byte-identical to the previous output)
• en / en+ja / undeclared / no roster → English (the new default; en+ja renders one chrome and English is the shared floor)

User data (decision titles, notes, labels, file paths) always passes through verbatim. There is deliberately no env-var or CLI-flag override: handoff.md / decisions.md are committed team artifacts, so their language is a project declaration, not a caller preference.

Changes

• New packages/core/src/lib/view-strings.ts — the single locale table (ViewLanguage, viewStrings(), resolveViewLanguage(), tolerant resolveViewLanguageFromPaths()), exported from @basou/core.
• All four renderers now select strings from the table and resolve the language themselves (mirroring the orientation renderer's tolerant source_roots manifest read), with an optional language input override for tests/programmatic callers — every call site (CLI commands, SDK, view server, codex context channel) follows automatically with zero wiring.
• E-5 allowlist (scripts/check-language.mjs) shrinks from the four renderer files to the one strings module; renderer sources are now English-only, structurally separating "user data language" from "tool chrome language".
• Tests: renderer tests now assert the English default; new manifest-driven ja tests per renderer (incl. en+ja → en and the explicit-override seam); new view-strings.test.ts unit-tests the resolution rules.
• Docs: docs/spec/generated-markdown.md gains §10.0 (view-language rule) and the templates now show the real English chrome. CHANGELOG documents the default flip under Unreleased.

Behavior change

Rendered prose only (explicitly outside the compatibility.md freeze): a workspace with no declared anchor language previously rendered Japanese headings and now renders English. Keeping Japanese = declare language: ja on the anchor entry.

Verification

• pnpm typecheck / pnpm build / pnpm lint / pnpm lint:lang green
• core 1324 / cli 984 / sdk 18 tests green
• Live: basou refresh against a language: ja fleet workspace keeps the exact Japanese chrome (headings byte-identical); a fresh basou init workspace renders the English chrome end-to-end (incl. the codex channel carrying the localized orientation body)

🤖 Generated with Claude Code