Add cloud clickpipe commands for managing ClickPipes

[markdawson]

Summary

Adds a cloud clickpipe command group for managing ClickPipes in ClickHouse Cloud, built on top of the clickhouse-cloud-api library client.

Commands

• list — list ClickPipes on a service
• get — get ClickPipe details (state, scaling, source, destination)
• create — create a ClickPipe; source type is a nested subcommand
• delete, start, stop, resync — lifecycle operations (resync is CDC-only)
• scale — update scaling configuration
• settings get|update — manage per-pipe settings

Create source types

clickpipe create uses nested subcommands, one per source:

• object-storage — S3, GCS, Azure Blob
• kafka — Kafka and Kafka-compatible, with TLS, SCRAM, and MSK IAM auth
• kinesis — Amazon Kinesis
• postgres, mysql, mongodb — CDC sources
• bigquery — BigQuery source

Other

• --json output supported for every subcommand
• Strict clap value validation on enum inputs (source type, auth mode, etc.)
• Unit tests for type serialization, state enum, scaling patch, settings, table mapping parsing, and destination deserialization
• Scaling, settings, and the postgres source block are treated as optional to match real API responses

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✅ sdairs
❌ markdawson
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[sdairs]

@markdawson looking good; one thing I notice is that the new tests in the clickhouse-cloud-api crate are invoking the CLI rather than the HTTP client.

The cloud integration tests should directly invoke the HTTP client (see the existing tests) and not the CLI.