Fix authentication handshake failure (Error 3020)

[djkoyi]

Problem

AltServer fails with "Failed to perform authentication handshake with server" (Error 3020) on macOS 15+/26. Authentication is completely broken because the SRP cryptographic code is disabled.

Root Cause

The MARKETPLACE compilation flag is set in both project.pbxproj and AltSign/Package.swift. This flag wraps all SRP authentication functions in #if MARKETPLACE blocks that return nil/false, making authentication impossible:

// GSAContext.swift - Every crypto function is disabled:
#if MARKETPLACE
return nil  // ← Always fails
#else
// actual SRP code
#endif

Additionally, the HTTP headers sent to gsa.apple.com contain outdated values from 2018-2019 (Darwin/18.7.0, Xcode 11.2) that create a TLS fingerprint mismatch with modern macOS.

Changes

1. Remove MARKETPLACE flag (the critical fix)

• AltStore.xcodeproj/project.pbxproj: Removed from SWIFT_ACTIVE_COMPILATION_CONDITIONS (Debug & Release)
• Dependencies/AltSign/Package.swift: Removed .define("MARKETPLACE") from swiftSettings

2. Update authentication headers

• User-Agent: Darwin/18.7.0 → Darwin/25.2.0
• X-Xcode-Version: 11.2 (11B41) → 26.2 (17C52) (in both ALTAppleAPI+Authentication.swift and ALTAppleAPI.m)

3. Update anisette device description

• Xcode bundle version in AnisetteDataManager.swift: 3594.4.19 → 24553

4. Fix macOS compatibility

• ProcessInfo+Device.swift: Added availability check for kIOMainPortDefault (macOS 12+) with fallback to kIOMasterPortDefault
• project.pbxproj: Updated libcorecrypto.tbd SDK path from MacOSX14.0.sdk to MacOSX26.2.sdk

Testing

• Built and tested on macOS 26.2 (Tahoe) with Xcode 26.2
• Successfully authenticated with Apple ID
• Successfully installed AltStore on iPhone