docs: bilingual credentials/settings-consumer documentation, catalogs, and gates

New credentials data-structure page (type-equiv manifested), group README,
rewritten llm-deepseek/llm-pi-ai READMEs (dynamic configuration, dict
profiles, credential chain), capability-seams/service-role registration,
Agent Note (bilingual), demo compositions mounting settings-local +
credentials-local with no inline key plumbing, installSettingsSection
consumer helper on the settings seam (deduplicating both adapters' wiring),
jscpd symmetry markers for the provider twins, runtime-closure additions for
python/sdk-runtime, and doc-budget ceilings AGENTS.md 1750→1755 /
packages/README.md 850→865 for the structural one-line group rows.

scripts/project-doc-site.spec.ts

@@ -197,7 +197,7 @@ describe('docsPages locale routes', () => {
     const translated = rootPages.filter(page => page.contentLocale === 'zh-CN')
     const fallbacks = rootPages.filter(page => page.contentLocale === 'en-US')
 
-    expect(translated).toHaveLength(19)
+    expect(translated).toHaveLength(20)
     expect(translated.every(page => page.source.endsWith('.zh.md'))).toBe(true)
     expect(fallbacks.map(page => page.source).sort()).toEqual([
       'docs/core-data-structures/commands.md',