Support multi-statement cloud query files

[sdairs]

Summary

• split cloud service query --queries-file input into ClickHouse-aware statements
• send each statement to the Query API sequentially, stream responses in order, and stop on the first failure
• support quoted strings and identifiers, ClickHouse comment forms, heredocs, Unicode quotes, and inline INSERT ... FORMAT data boundaries
• document independent-request/session-state and partial-application behavior

Root cause

The Query API accepts one SQL statement per request, but the CLI read a query file into one string and submitted the entire file in a single request. Local client --queries-file delegates to the native ClickHouse client, which already processes multi-statement files.

Impact

Multi-statement files, including --queries-file -, now execute in file order. Authentication, service resolution, and any Query API provisioning happen once. Earlier statements and output remain visible if a later statement fails; statements after the failure are not submitted.

Each statement is an independent Query API request, so persistent DDL/DML changes carry forward but connection-local state such as USE, SET, temporary tables, and transactions does not.

Stack

• Depends on Remediate ClickHouse Cloud OpenAPI drift #343
• Closes cloud service query --queries-file rejects multi-statement files that local client --queries-file accepts #333

Validation

• cargo fmt --all --check
• cargo build -p clickhousectl --all-targets
• cargo test -p clickhousectl
• cargo clippy -p clickhousectl --all-targets -- -D warnings