## What changed
- Include `environmentInfo` in the exec-server `initialize` response and seed the Rust client's metadata cache from it.
- Fall back to one lazy `environment/info` request when connecting to older servers that omit initialization metadata, then share the cached result across client clones and session recovery.
- Keep app-server `environment/info` requests uncached so they continue to probe the executor.
## Testing
- Cover initialization metadata, the legacy-server fallback, shared caching, accepted WebSocket environments, and repeated uncached app-server probes.
GitOrigin-RevId: 380132d9db183998d73e8c6b0954e4d70c7e8406
## What changed
- Make `ExecutorFileSystem::walk` a required backend operation instead of
providing a fallback built from directory reads and metadata requests.
- Implement bounded local walks on a blocking task with cancellation, symlink
cycle detection, deterministic ordering, error collection, and response-size
limits.
- Have remote filesystems use the server's walk operation directly.
## Testing
- Cover local and remote handling of invalid roots and limits, directory
symlinks, non-UTF-8 names, cancellation, sandbox contexts, and response
budgets.
GitOrigin-RevId: 7499bf05080c3f9965a5eb7ffd593de604d62c2a