test: real-Loader dynamic composition, keyless onboarding snapshot, and .env-only e2e

llm-deepseek gains a Loader+Include composition spec proving external
settings.yaml/.env edits reach the very next request, and a real-API e2e
where only a credentials-local document holds the key. The headless example
pins the first-run missing-credential UX as a keyless stream-json snapshot
(new credentials.cordis.snapshot.yml scenario); runLoaderSmoke learns
expectedExitCode so a designed failure surface can be pinned instead of
masked.

pnpm-lock.yaml

@@ -448,6 +448,9 @@ importers:
       '@deepseek-ai/dsh-compact-tool-result-prune':
         specifier: workspace:*
         version: link:../packages/compact/compact-tool-result-prune
+      '@deepseek-ai/dsh-credentials-local':
+        specifier: workspace:*
+        version: link:../packages/credentials/credentials-local
       '@deepseek-ai/dsh-fs-local':
         specifier: workspace:*
         version: link:../packages/fs/fs-local
@@ -529,6 +532,9 @@ importers:
       '@deepseek-ai/dsh-session-title-first-message-llm':
         specifier: workspace:*
         version: link:../packages/session-title/session-title-first-message-llm
+      '@deepseek-ai/dsh-settings-local':
+        specifier: workspace:*
+        version: link:../packages/settings/settings-local
       '@deepseek-ai/dsh-spill-local':
         specifier: workspace:*
         version: link:../packages/spill/spill-local