feat(legacy-meter): schedule 8h capture activity on railiance01

Add legacy-meter-8h-capture cron (0 */8 * * * UTC), pass hours through the
state-hub resolver, and label progress summaries by window size.

activity-definitions/legacy-meter-8h-capture.md

@@ -0,0 +1,31 @@
+---
+id: legacy-meter-8h-capture
+name: Legacy-Meter 8h Capture
+enabled: true
+owner: custodian-agent
+governance: custodian
+status: active
+trigger:
+  type: cron
+  cron_expression: "0 */8 * * *"
+  timezone: UTC
+  misfire_policy: skip
+context_sources:
+  - type: state-hub
+    query: legacy_meter_weekly_review
+    required: true
+    params:
+      hours: 8
+      evidence_sinks:
+        - type: state-hub-progress
+          event_type: legacy_meter_8h_capture
+          author: activity-core
+          workplan_id: 44e2e123-9934-4b5e-8b50-1bac548c5b70
+    bind_to: context.legacy_meter_weekly_review
+---
+
+# Legacy-Meter 8h Capture
+
+Runs every eight hours UTC. Fetches State Hub `/legacy-meter/weekly-review?hours=8`
+and posts `legacy_meter_8h_capture` progress for STATE-WP-0073 / STATE-WP-0070
+seven-window retirement gating.