add `FLUX_ENCLOSING_ID` to initial program environment for instances with a `jobid` broker attribute #10115

Job	Run time
Generate build matrix	7s
python linting	35s
validate commits	9s
spelling	7s
bookworm - test-install	1m 7s
bookworm - 32 bit	1m 6s
noble - test-install	1m 7s
el9 - test-install	1m 6s
alpine - test-install	1m 7s
fedora40 - test-install	1m 6s
jammy - test-install	1m 7s
focal - py3.8	1m 5s
bookworm - gcc-12,content-s3,distcheck	1m 6s
fedora40 - clang-18	1m 6s
coverage	1m 7s
el8 - ascii	1m 5s
el8 - test-install	1m 6s
el8 - system,coverage	1m 6s
inception	1m 6s
flux-accounting check	37s
macos build only	1s
flux-pmix check	1s
flux-pam check	38s
flux-sched check	1s
Generate docker manifest	1s
	18m 50s

Provide feedback