feat(s3stream): support per-bucket CRT S3 clients

[superhx]

Why

Object-storage clients currently use Netty for every bucket. Operators need an opt-in CRT S3 client to tune connection health and transfer resources independently for data, WAL, and ops buckets without introducing process-wide mutable settings.

What

Add per-bucket SDK selection and tuning through camel-case BucketURI options. Netty remains the default and existing SDK API call and attempt deadlines remain available on the Netty path. Reuse the existing AWS SDK and CRT dependencies.

Each bucket uses an independent immutable configuration; CRT-only options are ignored by Netty. Disable CRT automatic multipart uploads with a fixed Long.MAX_VALUE threshold, preserving AutoMQ's explicit multipart uploads and request-level precomputed checksums. CRT S3 does not support the standard SDK API call/attempt deadlines.

URI option	Default	Behavior
sdkImpl	netty	Selects netty or crt.
connectionTimeoutMs	2000	Connection establishment timeout for either implementation.
numRetries	2	Retries per HTTP request, excluding the initial attempt.
maxConcurrency	-1	Inherits AutoMQ's existing CPU-based client concurrency; explicit values affect the client cap, not the outer inflight quotas.
crtTargetThroughputInGbps	10	Per-client throughput target used for resource planning, not a bandwidth limiter.
crtMinimumThroughputInBps	33554432	Minimum healthy throughput per CRT connection.
crtMinimumThroughputTimeoutSeconds	2	Allowed low-throughput interval; values below two seconds are rejected.
crtMaxNativeMemoryLimitInBytes	-1	Leaves native memory budgeting to CRT.

Reviewer notes

Read AwsObjectStorage.Configuration.fromBucketURI and newS3Client first to follow parsing and SDK construction. BucketURI declares the shared option names. AwsObjectStorageTest covers configuration isolation and propagation, including the fixed automatic multipart threshold.

Connection health thresholds can interact with intentional throttling or host contention. Native memory budgets and throughput targets are per client and must be considered across all clients in a broker. Equal retry counts do not imply identical backoff behavior between Netty and CRT.

[superhx]

Validation: all 15 AwsObjectStorageTest tests, s3stream Checkstyle and SpotBugs passed. Whole-repository rat/checkstyleMain/checkstyleTest completed successfully (rat is disabled by this branch). The prescribed spotlessJavaCheck task does not exist on 1.7; Javadoc was excluded from targeted tests because of an external Oracle TLS handshake failure. Devkit produce/consume and broker-restart checks passed. Additional CRT PUT/read-back tests against Devkit MinIO passed for MD5 and CRC32 at 32 MiB minus one byte, 32 MiB, and 33 MiB with automatic multipart disabled. Devkit README has no changes in this PR.

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