fix: restore ability to build as a standalone static lib

[crleona]

Summary

Our Unreal SDK was previously linked against a statically built version of v8.1.0 of this SDK, and we've since added several updates. The following changes are required to maintain compatibility with Unreal:

• Adds a new Static Library build configuration, which compiles targets as individual static libraries vs dynamic libraries intended for use in frameworks
• Added the ability to exclude analytics connector for these static library builds, as experiment is not supported on the platform and it adds to linking complexity. To accomplish this we move the dependency for analytics connector from carthage to cocoapods, which allows us to only include it in certain configurations. I'm not sure why we decided to split dependencies between carthage and cocoapods in the first place.
• adds missing type annotations to AMPMiddlewarePayload
• AMPServerZone values are unprefixed, so we have US and EU global constants ☹️. These conflict with constants in Unreal. We add a compiler flag to actually use prefixed versions in certain environments since we can't break backwards compatibility.
• adds a quick generated build script
• cleans up some invalid project references

Checklist

• Does your PR title have the correct title format?
• Does your PR have a breaking change?: yes

[Copilot]

Pull Request Overview

This PR restores standalone static library build capability for the SDK to maintain compatibility with Unreal while also improving dependency management and addressing naming conflicts for server zones.

• Added a new build script for static library compilation across multiple platforms
• Updated server zone definitions to support prefixed constants in select environments
• Introduced conditional inclusion of the Analytics Connector and minor property attribute adjustments

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
scripts/build_static_libs.sh	Added a multi-platform build script for static library targets
Sources/Amplitude/Public/AMPServerZone.h	Applied a compiler flag to switch between prefixed and unprefixed enums
Sources/Amplitude/Public/AMPMiddleware.h	Updated property attributes and initializer declarations
Sources/Amplitude/Amplitude.m	Integrated conditional inclusion of Analytics Connector functionality
Sources/Amplitude/AMPServerZoneUtil.m	Updated switch cases to use new prefixed server zone constants
Podfile	Added use_frameworks and defined dependencies for Analytics Connector

[sojingle]

LGTM