This PR implements issue #3472 by splitting the monolithic zio-http artifact into three separate Maven modules:

Changes

1. zio-http-core (98 files)

Core types without Netty dependency:

• Request, Response, Handler, Routes, Body, Headers
• URL, Path, Method, Status, Cookie
• Codecs (codec/, internal/)
• Templates (template/, template2/)
• Multipart support

2. zio-http-endpoint (4 files)

Endpoint API:

• Endpoint, EndpointExecutor, EndpointLocator
• AuthType

3. zio-http-netty (8 files)

Netty-based implementation (JVM only):

• NettyBody, NettyChannel, NettyConfig
• NettyResponse, NettyRuntime

The main zio-http module now aggregates all three modules for backward compatibility.

Closes #3472

/claim #3472