Port Android/Skip build support (OpenCombine swap)

[poly-georgevisconti]

Summary

Ports the single-commit Android build fix from theleftbit/connect-swift@codex/fix-android-build onto our fork, preserving the original commit and authorship. Our main is at upstream v1.2.3 (ed56816), which is exactly the commit the fix was written against, so this is a clean fast-forward.

The fix makes connect-swift build and pass tests under Skip/Android, primarily by swapping Combine for OpenCombine plus small portability adjustments (locking, logging, URLSession streaming) across 20 files.

Why

Polymarket/swift-proto-gateway-us (the generated Connect bindings package consumed by the mobile app) currently depends on theleftbit's fork as a POC. To take that dependency in-house it needs this commit on our fork; after merge, main will be tagged 1.2.3-polymarket.1 and the bindings package pinned to that tag.

Test plan

• Upstream v1.2.3 plus this exact commit is what swift-proto-gateway-us has been building against throughout the POC (iOS + Skip/Android).
• After merge + tag, swift-proto-gateway-us will be re-pinned and resolved/built against it.

🤖 Generated with Claude Code

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Note

Medium Risk
Threading changes (NSRecursiveLock vs os_unfair_lock) and Darwin-only URLSession affect core HTTP paths on Apple; non-Darwin builds rely on NIO and OpenCombine, which is a new dependency surface for mocks.

Overview
Adds Skip/Android build support by making Apple-only APIs optional and supplying OpenCombine where Combine is unavailable.

ConnectMocks and generated mock code now import OpenCombine when Combine is missing; Package.swift pins OpenCombine 0.15.1. ConnectMockGenerator emits the same conditional imports.

URLSession-based HTTP (URLSessionHTTPClient, URLSessionStream) is wrapped in #if canImport(Darwin). ProtocolClient’s default URLSessionHTTPClient() convenience initializer is Darwin-only; non-Darwin callers must pass an explicit HTTPClientInterface (e.g. NIO). Conformance CLI and tests gate the urlsession client and URLSession-specific integration tests behind Darwin.

Lock switches from os_unfair_lock to NSRecursiveLock. os_log calls are guarded with #if canImport(OSLog); HTTPMetrics optionally imports FoundationNetworking.

CI bumps Xcode to 26.4.1 and actions/checkout to v7. The add-to-project workflow is removed.

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[poly-georgevisconti]

CI triage

All 8 failures investigated; only 2 were actually caused by the ported commit, and both were cosmetic. Fixed in the two follow-up commits:

Check	Cause	Fix
build-library-ios / tvos / watchos, eliza-swiftpm	Environment: the macos-26 runner image no longer ships the iOS/tvOS/watchOS 26.1 platform SDKs, so the pinned Xcode 26.1.1 finds no build destinations	Synced ci.yml with upstream main (Xcode 26.4.1, checkout@v7) — upstream is green on this exact config
run-conformance-tests	Same stale-toolchain issue, not the code: the ported commit passes the full URLSession conformance suite locally on a current Xcode — 966/966 cases	Covered by the Xcode bump
run-swiftlint	Real: whitespace in Lock.swift, string-literal alignment in UnaryAsyncWrapper.swift (both files touched by the port)	Fixed
validate-license-headers	Real: missing blank line after the header in 2 files, plus Logging.swift — an empty file accidentally added by the port	Ran make licenseheaders; deleted the empty file
Add issue to project	Calls connectrpc's internal reusable workflow (connectrpc/base-workflows) with an org App credential we don't have — can never pass on this fork	Deleted the workflow. Note: it runs from the base branch (pull_request_target), so its red ❌ will linger on this PR until merge; harmless

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