feat(license): distributed license enforcement across multi-node setups (#359)

* feat(license): distributed license enforcement across multi-node setups

The primary instance's license tier is now asserted to remote nodes on
every proxied HTTP and WebSocket request via trusted headers. Remote
nodes honor the assertion only when the request carries a valid
node_proxy JWT, preventing unauthorized elevation from browsers or API
tokens. Falls back to local license tier for direct access.

* fix(test): remove unused vi import in distributed-license tests

CHANGELOG.md

@@ -24,6 +24,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * **fleet:** remote node update management (Pro tier) — check for outdated nodes and trigger over-the-air updates from Fleet View. Nodes self-update by pulling the latest Docker image and recreating their container. Includes version badges on node cards, per-node and bulk "Update All" actions, real-time progress tracking with 5-second polling, reconnecting overlay for local node updates, and `POST /api/system/update` endpoint for programmatic self-updates. Requires Docker Compose deployment with Docker socket access.
 
+* **license:** distributed license enforcement across multi-node setups — the primary instance's license tier (Skipper/Admiral) is now automatically asserted to remote nodes on every proxied request. Remote nodes honor the assertion only when the request arrives with a valid node proxy token, preventing unauthorized elevation. No per-node license activation required. Includes type guards and header constants in `LicenseService`, and comprehensive test coverage for all trust chain scenarios.
+
 ## [0.32.0](https://github.com/AnsoCode/Sencho/compare/v0.31.0...v0.32.0) (2026-04-03)