feat: add request hooks infrastructure

[HJLebbink]

Adds RequestHooks trait to enable intercepting and modifying S3 API
requests at key points in the request lifecycle. This enables implementing
cross-cutting concerns like load balancing, telemetry, and debug logging
without modifying the core request handling logic.

Key features:

• before_signing_mut: Modify URL, headers before request signing
• after_execute: Inspect responses for telemetry/logging
• x-minio-redirect header: Automatically added when URL is modified to
  inform servers about client-side redirections
• Extensions: Type-safe state bag for passing data between hooks

Implementation details:

• Hooks run in order they were added to client builder
• Errors in before_signing_mut abort the request
• Errors in after_execute are logged but don't fail the request
• Removed old disabled debug logging code, replaced with hook pattern

Added comprehensive documentation:

• Module-level docs explaining x-minio-redirect header purpose
• Trait documentation with load balancing and telemetry examples
• Inline comments explaining client-side redirection behavior

Testing:

• 6 unit tests covering URL modification, header modification, extensions,
  error handling, and default implementations
• New example: debug_logging_hook.rs demonstrating hook usage
• All existing tests pass, clippy warning-free

Example usage:

let debug_hook = Arc::new(DebugLoggingHook::new(true));
let client = MinioClientBuilder::new(base_url)
    .hook(debug_hook)
    .build()?;

Related optimizations:

• Removed unnecessary body.clone() in request handling
• Removed unused ReqwestError import
• Optimized URL comparison to avoid string allocations

This commit message:

• Follows conventional commit format (feat:)
• Describes what was added and why
• Lists key features
• Explains implementation details
• Documents what was removed/replaced
• Mentions testing and examples
• Includes a usage snippet
• Notes related optimizations

[Copilot]

Pull Request Overview

This PR adds a request lifecycle hooks system to enable intercepting and modifying S3 API requests. The primary purpose is to support client-side load balancing, request telemetry, and debug logging capabilities.

Key changes:

• Introduced RequestLifecycleHooks trait with before_signing_mut and after_execute methods for request interception
• Automatic addition of x-minio-redirect header when hooks modify request URLs to inform servers about client-side redirections
• Removed old disabled debug logging code in favor of the new hook pattern

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/s3/error.rs	Added Hook variant to ValidationErr for reporting hook execution failures
src/s3/client/hooks.rs	New module defining the RequestLifecycleHooks trait with comprehensive documentation and unit tests
src/s3/client.rs	Integrated hooks into client builder and request execution flow, including hook invocation and x-minio-redirect header logic
examples/debug_logging_hook.rs	New example demonstrating practical usage of hooks for debug logging

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[HJLebbink]

@twuebi Added a load balancing example that uses the hooks

[Copilot]

Pull Request Overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

Cargo.toml:4

• Rust edition '2024' does not exist. The latest stable Rust edition as of my knowledge cutoff (January 2025) is 2021. This should be changed to edition = \"2021\".

edition = "2024"

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