refactor: unify CocoaPods distribution with single podspec

[thomson-t]

Summary

• Consolidate the SDK's CocoaPods distribution by folding umbrella Swift sources (MParticle/Sources/) into the main mParticle-Apple-SDK.podspec and removing the separate mParticle-Apple-SDK-Umbrella pod
• Restore module_name = mParticle_Apple_SDK (matching v8.x) so consumer imports (@import mParticle_Apple_SDK; / import mParticle_Apple_SDK) are backward-compatible
• Use #if COCOAPODS conditional in kit ObjC headers to resolve module name differences between CocoaPods (mParticle_Apple_SDK) and SPM (mParticle_Apple_SDK_ObjC)
• Simplify CI workflows to lint/publish a single core podspec

Motivation

The previous approach on feat/support_cocopods split the SDK into 3 separate CocoaPods pods and changed the ObjC module name to mParticle_Apple_SDK_ObjC, breaking backward-compatible imports for consumers. This PR replaces that approach with a single-podspec structure that preserves the v8.x import patterns.

Changes

Area	What changed
Core podspec	module_name restored to mParticle_Apple_SDK; umbrella Swift sources folded in; mParticle-Apple-SDK-Swift kept as dependency (required by Xcode build system)
Swift exports	mParticleAppleSDKExports.swift uses #if !COCOAPODS guard for the ObjC module re-export
Kit headers	All 34 kit ObjC files use #if COCOAPODS @import mParticle_Apple_SDK; #else @import mParticle_Apple_SDK_ObjC; #endif
Rokt kit podspec	Fixed path() dependency bug; uses USE_LOCAL_VERSION env var for local dev
CI	build-and-lint.yml, build-kits.yml, release-publish.yml simplified to single podspec
Example app	Removed stale Media SDK import; simplified Podfile

Test plan

• pod lib lint mParticle-Apple-SDK.podspec passes
• pod lib lint mParticle-Rokt.podspec passes
• pod install + workspace build in Example/ succeeds
• SPM build of core SDK (xcodebuild -scheme mParticle-Apple-SDK) succeeds
• SPM build of Rokt kit (mParticle-Rokt.xcodeproj) succeeds
• Rokt kit SPM-Swift-Example builds
• Rokt kit SPM-Objc-Example builds
• CI pipeline passes (pending)

[github-actions]

📦 SDK Size Impact Report

Measures how much the SDK adds to an app's size (with-SDK minus without-SDK).

Metric	Target Branch	This PR	Change
App Bundle Impact	1.75 MB	1.75 MB	+N/A
Executable Impact	848 bytes	848 bytes	+N/A
XCFramework Size	6.38 MB	6.38 MB	+N/A

➡️ SDK size impact change is minimal.

Raw measurements

Target branch (main):

{"baseline_app_size_kb":84,"baseline_executable_size_bytes":75464,"with_sdk_app_size_kb":1880,"with_sdk_executable_size_bytes":76312,"sdk_impact_kb":1796,"sdk_executable_impact_bytes":848,"xcframework_size_kb":6532}

This PR:

{"baseline_app_size_kb":84,"baseline_executable_size_bytes":75464,"with_sdk_app_size_kb":1880,"with_sdk_executable_size_bytes":76312,"sdk_impact_kb":1796,"sdk_executable_impact_bytes":848,"xcframework_size_kb":6532}