Add Standalone Activities to Temporal Nexus Operation Handler #3029

Job	Run time
Unit test with in-memory test service [Edge]	10m 53s
Unit test with cloud	33s
Code format	1m 34s
Javadoc	3m 31s
Unit test with CLI	11m 56s
Build native test server / Build native test server (windows-latest, windows, amd64)	6m 27s
Build native test server / Build native test server (ubuntu-latest, linux, amd64, false)	6m 42s
Build native test server / Build native test server (ubuntu-latest, linux, amd64, true)	5m 7s
Build native test server / Build native test server (ubuntu-24.04-arm, linux, arm64)	5m 48s
Build native test server / Build native test server (macos-latest, macOS, arm64)	11m 44s
Build native test server / Build native test server (macos-15-intel, macOS, amd64)	5m 54s
	1h 10m 9s

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