Fix: handle chunked HTTP responses in client

[echobt]

Summary

• Parse HTTP headers to respect Transfer-Encoding and Content-Length.
• Decode chunked bodies before JSON deserialization.
• Reuse a response body reader for search and embed_batch.

Problem

The TCP-based client ignored Transfer-Encoding and Content-Length, so chunked responses included size markers in the body and broke JSON parsing.

Solution

Read the status line and headers, detect chunked encoding or a content length, decode the body accordingly, then parse JSON.

Testing

• cargo fmt --check --manifest-path C:\Users\Hi\PROJECTS\temp_gXLtjamd\Cargo.toml
• cargo clippy --all-targets --all-features --manifest-path C:\Users\Hi\PROJECTS\temp_gXLtjamd\Cargo.toml (failed: missing libclang.dll)
• cargo test --manifest-path C:\Users\Hi\PROJECTS\temp_gXLtjamd\Cargo.toml (failed: missing libclang.dll)

Related Issue

Fixes PlatformNetwork/bounty-challenge#38