Release v0.28.16

What's Changed

• fix(auth): handle transient OAuth responses by @overlord-letta in #3425
• fix(mods): avoid eager React resolution in packaged runtimes by @overlord-letta in #3439
• fix(cli): isolate image processing diagnostics [LET-9916] by @cpacker in #3434
• refactor(cli): retire Constellation terminology [LET-9905] by @cpacker in #3431
• fix(agent): clarify stale-approval auto-close denial reason by @cpacker in #3444
• fix(prompts): give Tutor a dedicated human prompt by @sarahwooders in #3375
• feat: add task-first Tutor guidance and active config inspection by @cpacker in #3442
• chore: bump version to 0.28.16 by @github-actions[bot] in #3452

Full Changelog: v0.28.15...v0.28.16