Archive demo-activity-bot, pg-boss-background-jobs, configurable-demo-persona

Fold completed deltas into main specs (activity-feed, route-management,
infrastructure, planner-session), add new background-jobs and
demo-activity-bot capability specs, and move the three change dirs to
openspec/changes/archive/.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

openspec/specs/planner-session/spec.md

@@ -40,3 +40,20 @@ The Planner SHALL synchronize waypoint edits, route options, and overlay prefere
 - **WHEN** a participant reloads the session page
 - **THEN** the notes content is restored from the Yjs document
 - **AND** the editor displays the existing text immediately
+
+### Requirement: Session expiry
+Open sessions with no activity for 7 days SHALL be automatically deleted by a scheduled background job.
+
+#### Scenario: Stale session cleanup
+- **WHEN** the hourly `expire-sessions` cron job runs
+- **THEN** all sessions with `last_activity` older than 7 days are deleted from the database
+- **AND** their Yjs documents are removed from memory
+
+#### Scenario: Active session preserved
+- **WHEN** the `expire-sessions` job runs
+- **THEN** sessions with `last_activity` within the last 7 days are NOT deleted
+
+#### Scenario: Cleanup is observable
+- **WHEN** the `expire-sessions` job completes
+- **THEN** the job output includes the count of expired sessions
+- **AND** the result is visible in the Grafana job queue dashboard