Fix SIGINT handling: re-raise signal instead of exit(130)

[4RH1T3CT0R7]

• Fix docker compose pull (and all other commands) to properly re-raise SIGINT/SIGTERM after cleanup instead of exiting with code 130. This ensures parent processes see WIFSIGNALED=true via waitpid(), enabling correct WCE (Wait and Cooperative Exit) shell propagation.
• Propagate context cancellation error from pullServiceImage instead of swallowing it, so concurrent pulls stop immediately on Ctrl+C.

Problem

When a user presses Ctrl+C during docker compose pull, the process exits via os.Exit(130). The parent shell's waitpid() sees WIFEXITED=true (normal exit), not WIFSIGNALED=true (signal death). This breaks shell script interrupt handling — the parent script continues executing instead of stopping.

Fixes #13586

[4RH1T3CT0R7]

@ndeloof Good point! Since up_test.go already has a //go:build !windows constraint, the process will always die from the re-raised signal on this platform. Simplified the assertion to expect exactly -1 instead of == -1 || == 130. Thanks for the review!