docs: the sample configuration in design document 08 does not load #585

Summary

The sample configuration in docs/design/08-component-config.md section 3 does not load. Both ServerConfig and PostgresStorageConfig carry #[serde(deny_unknown_fields)], and the sample sets keys neither struct has, so a server started from a copy of it stops at startup with an unknown field error.

Keys in the sample that no struct has

[server] (crates/config/src/lib.rs, fields bind_addr, port, region, run_dir, tls, throttling_enabled):

• max_connections
• request_timeout_secs
• shutdown_drain_secs
• max_request_size_bytes
• the [server.rate_limit] table (global_rps, per_table_rps)

[storage.postgres] (crates/storage-postgres/src/config.rs, fields connection_string, pool_size, catalog_pool_size):

• connection_timeout_secs
• statement_timeout_secs

The read_replica_url and read_replica_pool_size lines were removed by #584 (issue #561). The rest of the sample has the same defect.

Expected

The sample loads as written, or each key it shows is one the loader accepts. The operator reference in docs/manuals/05-admin-guide.md lists the [storage.postgres] keys the loader has and can serve as the source for the sample.

Where

• docs/design/08-component-config.md, section 3, the [server] block and the [storage.postgres] block
• crates/config/src/lib.rs, ServerConfig
• crates/storage-postgres/src/config.rs, PostgresStorageConfig