/gsd-next silently skips partially-executed phases when current_phase was advanced past unfinished work (data-loss-shape)

### GSD Version main at commit 8b6ffca5 (verified against current master) ### Runtime Claude Code ### Operating System macOS ### Node.js Version v22.x ### Shell /bin/zsh ### Installation Method Other: verified against the redux source tree directly (downstream plugin packaging) ### What happened? When a session dies mid-execution (hang, token exhaustion, API connection disruption) during `/gsd-execute-phase N`, STATE.md's `current_phase` can be left advanced past `N` (e.g., set to `N+1`) even though phase `N` still has plans without matching SUMMARY.md files. On the next session, running `/gsd-next` (or `/gsd-progress --next`) enters the workflow at `get-shit-done/workflows/next.md`: 1. `safety_gates` § Prior-phase completeness scan (line 96) detects the situation: phase `N` has plans without summaries while `current_phase` is `N+1`. 2. The scan emits its structured prompt offering three options: `[C] Continue and defer to backlog`, `[S] Stop and resolve manually (default)`, `[F] Force advance without recording deferral`. 3. **There is no "Resume phase N" option.** If the user picks Stop (the documented default), the workflow exits without routing. The user then has to manually inspect STATE.md, figure out what was running, and invoke `/gsd-execute-phase N` themselves. If the user picks Continue-and-defer, the workflow: - Files each unfinished plan to a `999.x` Backlog entry in ROADMAP.md - Commits the deferral - Routes to `determine_next_action`, which then ...