ci: add SonarQube coverage pipeline (blueprint)

[alghanor]

Adds a SonarQube coverage pipeline for Telegraph. Draft — the build approach needs to change (see below).

Corrected diagnosis (why the xcworkspace approach fails)

tillhub/Telegraph is a fork of Building42/Telegraph whose purpose is to depend on the patched tillhub/CocoaAsyncSocket 7.6.7 (a tag that doesn't exist upstream) — wired through Package.swift (SPM):

.package(url: "https://github.com/tillhub/CocoaAsyncSocket.git", from: "7.6.7")   // fork
// upstream: robbiehanson/CocoaAsyncSocket from 7.6.5

The legacy Telegraph.xcworkspace / Telegraph iOS scheme was inherited from upstream and never updated for the fork:

• its XCRemoteSwiftPackageReference still points at robbiehanson/CocoaAsyncSocket (7.6.4) — so building via the scheme ignores the fork's whole point;
• the Telegraph Tests target links neither Telegraph.framework nor sets BUNDLE_LOADER (host app links nothing) → ld: framework 'Telegraph' not found.

Upstream Building42 CI uses that same legacy scheme (and a stale iPhone 14 Pro sim), so it isn't a reliable blueprint either.

Recommended fix (low-risk, no .pbxproj surgery)

Test via SPM instead of the xcworkspace:

• swift build / swift test --enable-code-coverage against Package.swift (resolves the tillhub CocoaAsyncSocket 7.6.7 fork; TelegraphTests correctly depends on Telegraph).
• Coverage: xcrun llvm-cov export -format=lcov … → convert lcov to Sonar generic format for sonar.coverageReportPaths (the xccov script in this PR does not apply to SPM).
• Consider retiring or updating the stale Telegraph.xcworkspace.

The sonarqube.yaml scan config here (sources Sources, tests Tests) is still valid; only the Unit Tests build step needs to move to SPM.

🤖 Generated with Claude Code