Fix web/frontend compat bugs in managed config & runtime status
- Preserve [[peer]].peer_public_key when TOML configs round-trip
through the web/managed NetworkConfig path
- Keep old peer_urls clients working while adding structured peer
metadata for new clients
- Make frontend protobuf JSON normalization preserve omitted-field
semantics instead of turning missing data into misleading defaults
- Harden runtime status rendering against omitted or string-encoded
backend fields
- Expose peer-route feature flags in the web status UI
* refactor(web): use generated proto network types
* fix(core): preserve dumped config flags
* test(web): cover config flag save paths
* fix(ci): use system protoc before frontend codegen
* fix(ci): serialize frontend-lib builds