feat: full http client with fetch support

[zees-dev]

Description

This pull request introduces significant changes to the blockless-sdk dependency, adds a new comprehensive example for the fetch API, and removes legacy Rust code related to HTTP handling. Below is a summary of the most important updates:

Dependency Updates:

• Updated the blockless-sdk dependency in Cargo.toml to use a specific Git revision (368b6b81) from the repository instead of a versioned release. This ensures the project uses the latest code from the SDK's source.

New Examples:

• Added a detailed example in examples/fetch.js demonstrating the use of a fetch-compliant wrapper around the HTTP client. This includes multiple use cases such as GET, POST, PUT, DELETE, PATCH requests, error handling, response cloning, and headers manipulation.

Codebase Simplification:

• Removed the src/fetch/blockless.rs file, which contained legacy Rust code for HTTP handling, including the BlocklessHttp struct, HttpOptions, and related functions. This cleanup eliminates unused code and reduces technical debt.

Pre-requisites

• feat: full http client with fetch support #15

[Copilot]

Pull Request Overview

This PR replaces the legacy Rust HTTP handler with a fetch-compliant Rust implementation (bless_fetch_request), adds a full JavaScript polyfill for fetch, Request, Response, Headers, and FormData, provides a detailed example script, and updates dependencies and CI matrix.

• Swapped blockless-sdk on crates.io to a Git revision in Cargo.toml
• Introduced src/fetch/mod.rs with a full fetch client and response builder
• Added src/fetch/fetch.js polyfill and examples/fetch.js demo, and removed legacy src/fetch/blockless.rs

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/fetch/mod.rs	New Rust fetch implementation, option parsing, JS response creation
src/fetch/fetch.js	JavaScript fetch polyfill with Request, Response, Headers, FormData
src/fetch/blockless.rs	Removed legacy HTTP binding
examples/fetch.js	Comprehensive fetch usage examples
Cargo.toml	Updated blockless-sdk to a Git revision
.github/workflows/release.yml	Adjusted build matrix ordering and targets

Comments suppressed due to low confidence (3)

examples/fetch.js:107

• The new fetch implementation has many code paths (FormData, ArrayBuffer, JSON, etc.) but there are no tests covering these branches; consider adding unit tests or example snippets that exercise each path.

        const multiHeaders = new Headers();

.github/workflows/release.yml:22

• There is a trailing comma in the flow-style YAML list; while some parsers allow it, it can cause CI failures—please verify YAML validity or remove the trailing comma.

          { name: 'full', features: '--all-features' },

src/fetch/mod.rs:10

• [nitpick] Public functions and types (like bless_fetch_request, FetchOptions, BodyInit) lack module-level or doc comments explaining their purpose—consider adding top-level documentation for maintainability.

/// A fetch-compliant HTTP client