* feat(core): add optional reply footer metadata
* feat(config): enable reply footer by default
* feat(codex): use runtime footer metadata from app-server
* feat(codex): resolve exec footer metadata at runtime
* feat(core): style reply footer and prefer context left
* feat(codex): use real runtime context for reply footer
* feat(core): use english left footer text
* fix(codex): use current context tokens for footer left
* fix(codex): match cli context left calculation
* test(codex): adapt footer tests to session base url arg
