Standalone installs fixed; code-mode falls back to embedded runtime

Bug Fixes

• Fixed standalone installs failing when GitHub returns compact or reordered release metadata. (#31913)
• Ensured macOS package installs expose the code-mode host alongside the codex executable. (#31913)
• Kept code mode working when the companion host binary is unavailable by falling back to the embedded runtime. (#31913)

Changelog

Full Changelog: rust-v0.144.0...rust-v0.144.1

• #31913 [0.144] Backport installer and code-mode reliability fixes @bolinfest