Simplify early Bash helper APIs

[codeforester]

Summary

• remove early compatibility aliases: run, std_run_with_timeout, and str_in_array
• keep std_run --timeout as the timeout API and list_contains as the membership API
• update docs/changelog and clarify list_remove duplicate removal coverage

Fixes #106

Validation

• bats lib/bash/std/tests/lib_std.bats
• bats lib/bash/str/tests/lib_str.bats
• bats lib/bash/list/tests/lib_list.bats
• ./tests/validate.sh
• git diff --check