fix cross-shard ORDER BY on non-projected columns

[murex971]

• Temporarily project missing ORDER BY columns during query rewriting.
• Use hidden columns for correct global cross-shard sorting.
• Remove hidden columns before sending rows and RowDescription to clients.
• Support direct-shard results.
• closes [Query Engine] ORDER BY on non-projected column can produce incorrect cross-shard ordering #1135

[codecov]

Codecov Report

❌ Patch coverage is 97.16981% with 12 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...dog/src/backend/pool/connection/multi_shard/mod.rs	70.58%	5 Missing ⚠️
...ontend/router/parser/rewrite/statement/order_by.rs	97.12%	4 Missing ⚠️
pgdog/src/frontend/client/query_engine/query.rs	97.77%	1 Missing ⚠️
pgdog/src/frontend/router/parser/query/select.rs	96.96%	1 Missing ⚠️
pgdog/src/net/messages/bind.rs	90.90%	1 Missing ⚠️

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[levkk]

Aren't we calling drop_columns twice now? Once in multi shard binding, and once here, so twice for multi-shard queries and once for direct-to-shard queries.

[levkk]

I would probably push this concern into the connection binding (e.g.. read method). The architecture is as such that piece of code handles the cross-shard/direct-to-shard message manipulation. The query engine doesn't actually know whether it's talking to one or more servers, so this leaks it here.