docs(s3s): add and improve module-level docs across all modules

[Copilot]

• Add module-level docs to checksum.rs
• Add module-level docs to crypto.rs — fix: "Cryptographic hash primitives" → "Checksum and hash primitives"; distinguish CRC (non-cryptographic) from SHA/MD5 (cryptographic)
• Add module-level docs to dto/mod.rs
• Add module-level docs to error/mod.rs
• Add module-level docs to header/mod.rs
• Add module-level docs to host.rs
• Add module-level docs to stream.rs
• Add module-level docs to xml/mod.rs
• Add module-level docs to http/mod.rs
• Add module-level docs to ops/mod.rs
• Add module-level docs to utils/mod.rs
• Improve docs in post_policy.rs
• Improve docs in sig_v2/mod.rs
• Improve docs in sig_v4/mod.rs
• Improve docs in validation.rs — fix: "bucket and object names" → "bucket names" (trait only validates bucket names)
• Fix lib.rs: add missing region module to the # Modules list

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[Copilot]

Pull request overview

Adds and expands Rustdoc //! module-level documentation throughout the s3s crate to better explain each module’s purpose and key types, improving discoverability for users implementing S3-compatible services.

Changes:

• Added new module-level docs for core modules like xml, stream, http, ops, dto, error, checksum, and crypto.
• Expanded existing docs for post_policy, sig_v2, sig_v4, and validation.
• Updated lib.rs module list to include the missing region entry.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/s3s/src/xml/mod.rs	Documents XML (de)serialization traits and wire-format conversion role.
crates/s3s/src/validation.rs	Expands docs for validation API (needs a small accuracy tweak).
crates/s3s/src/utils/mod.rs	Adds brief internal-module description.
crates/s3s/src/stream.rs	Documents byte-stream abstractions used for request/response bodies.
crates/s3s/src/sig_v4/mod.rs	Clarifies SigV4 scope (header, presigned URL, POST).
crates/s3s/src/sig_v2/mod.rs	Clarifies SigV2 as legacy and describes scheme.
crates/s3s/src/post_policy.rs	Improves module description for POST policy parsing/validation.
crates/s3s/src/ops/mod.rs	Documents internal operation dispatch + HTTP conversion responsibilities.
crates/s3s/src/lib.rs	Adds region to the documented module list.
crates/s3s/src/http/mod.rs	Documents internal HTTP utilities and helpers.
crates/s3s/src/host.rs	Documents virtual-host parsing and routing types.
crates/s3s/src/header/mod.rs	Documents generated S3 header-name constants.
crates/s3s/src/error/mod.rs	Documents error types, codes, and construction macro.
crates/s3s/src/dto/mod.rs	Documents Smithy-generated DTO re-exports and their role in S3 implementations.
crates/s3s/src/crypto.rs	Documents checksum/hash primitives (needs a small accuracy tweak).
crates/s3s/src/checksum.rs	Documents multi-algorithm, single-pass checksum computation.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[Nugine]

@copilot

1. apply changes based on the comments in this thread if necessary
2. merge current main branch