experiment: Add "swift" identityMode — Swift-owned identity cache #48

Job	Run time
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	3m 35s
Test BridgeJS against Swift versions (swift:6.3, 603.0.0)	2m 55s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	2m 54s
format	35s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	2m 39s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	3m 37s
prettier	8s
check-bridgejs-generated	2m 44s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	3m 34s
build-examples	47m 10s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 22s
Build for native target (macos-15, Xcode_16.4)	3m 12s
deploy-examples	1s
	1h 16m 26s

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