* feat(retention): prune old agent transcripts + panel-tunable setting
Agents write a {session-id}.jsonl per spawn under ~/.claude/projects; nothing
ever deleted them, so the operator's bind-mounted ~/.claude grew without bound.
Add a throttled orchestrator sweep that prunes agent-owned transcripts (the
shared -app dir + per-workspace dirs) older than a retention window — and ONLY
agent-owned dirs, never the operator's own Claude sessions (proven by the
temp-dir selection tests). The window is panel-tunable: a new system_settings
key-value table (migration 027) holds transcript_retention_days, read via
SettingsService with the roboco.config default (14d) as the fallback, exposed
through GET/PUT /api/settings. Panel wiring follows.
* feat(panel): add a panel-tunable transcript retention control
Wire the settings page to the /api/settings backend: a settings API client and
a self-contained Transcript Retention card (React Query) that loads
transcript_retention_days and saves it back, with client-side validation. The
existing settings controls are unchanged.
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Co-authored-by: Renn F <rennf93@users.noreply.github.com>
