Enriches the architect's existing sprint plan with:
1. Side effects: this sprint indirectly closes#665 (edge cold-start race) by
removing the runtime clone — flagging so a parallel #665 fix isn't applied.
2. Four follow-up sprints that complete the client-box upgrade story:
- A: 'disinto upgrade <version>' subcommand for atomic client-side upgrades
- B: unify DISINTO_VERSION and AGENTS_IMAGE into one version concept
- C: migration framework for breaking changes (per-version migration files)
- D: bootstrap-from-broken-state runbook for existing drifted boxes (harb)
3. Updated recommendation that sequences the follow-ups against this sprint
and notes #665 should not be fixed in parallel.
The original sprint scope (4 files, ~80% gluecode, GHCR) is unchanged and
remains tightly scoped. The follow-ups are deliberately kept inside this
document rather than filed as separate forge issues until the sprint plan is
ready to be broken into sub-issues by the architect.
