Add Ser/De + roundtrip protocol benchmarks

[RanVaknin]

Benchmarking notes

1. Isolated serialization/deserialization — uses the lowest-level public marshalling/unmarshalling API in each SDK. Due to architectural differences between v1 and v2, the deserialization benchmarks have one minor asymmetry worth noting:
   For JSON/RestJson/CBOR deserialization, v2's narrowest unmarshalling entry point takes an SdkHttpFullResponse, so the v2 benchmarks create an SdkHttpFullResponse wrapper per iteration. v1's narrowest entry point takes a raw parser, so it doesn't have this overhead. Even though v2's deserialization benchmark is slightly disadvantaged, it is faster across the board.

Protocol	Operation	V1 (ops/µs)	V2 (ops/µs)	Delta
RestJson	CreateFunction deser	0.068	0.176	+159%
RestJson	CreateFunction ser	0.468	0.284	-39%
JSON	DynamoDB PutItem deser	0.072	0.141	+96%
JSON	DynamoDB PutItem ser	0.139	0.101	-27%
CBOR	CloudWatch GetMetricData deser	0.279	0.382	+37%
CBOR	CloudWatch GetMetricData ser	0.719	0.416	-42%
EC2	DescribeInstances deser	0.014	0.019	+36%
EC2	DescribeInstances ser	1.724	1.068	-38%
Query	STS AssumeRole deser	0.037	0.038	+3%
Query	STS AssumeRole ser	3.181	1.394	-56%
RestXml	CloudFront CreateDistribution deser	0.004	0.005	+25%
RestXml	CloudFront CreateDistribution ser	0.047	0.079	+68%

2. Stubbed response roundtrip — full SDK client call through a local Jetty servlet that returns canned responses. Measures the entire request/response pipeline. v1 uses its default HTTP client; V2 uses Apache 5.

Protocol	Operation	V1 (ops/s)	V2 (ops/s)	Delta
RestJson	Lambda#CreateFunction	6,832	5,502	-19.5%
JSON	DDB#PutItem	6,389	5,078	-20.5%
CBOR	CW#GetMetricData	6,804	5,487	-19.3%
EC2	EC2#DescribeInstances	4,168	3,717	-10.8%
Query	STS#AssumeRole	5,319	4,739	-10.9%
RestXml	CF#CreateDistribution	2,034	2,036	+0.1%

[sonarqubecloud]

Quality Gate failed

Failed conditions
6 Security Hotspots
7.2% Coverage on New Code (required ≥ 80%)
3.1% Duplication on New Code (required ≤ 3%)
E Security Rating on New Code (required ≥ A)
E Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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[github-actions]

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