Merge remote-tracking branch 'origin/codex/invariant-service-seam' into codex/invariant-package-registration-gate

# Conflicts:
#	.agents/notes/implemented/architecture/2026-07-19-package-owned-invariant-service.i18n.yaml
#	docs/core-data-structures/session.md
#	docs/module-graph.md
#	package.json
#	packages/sdk/scripts/tsconfig.json

packages/llm/token-meter/README.md

@@ -42,6 +42,10 @@ Both plugins have usable defaults. A deployment with a different capacity config
 
 Indirectly, through consumers such as `dsh-compact-basic`; the service itself adds no prompt, message, schema, tool, or model call.
 
+#### KV Cache effect
+
+No direct invalidation; the named consumer owns any request-prefix changes.
+
 ## Known Limitations and Deferred Work
 
 - **The fixed heuristic is approximate** — content without reusable provider usage is priced by character count plus structural overhead, not an exact provider tokenizer or request serializer.