feat(PMEM-WP-0017): federated store management CLI and activity reports

Add phase_memory.management for cross-store discovery and windowed
activity reporting. Extend the phase-memory CLI with stores list and
report commands, plus make report-7d for the default weekly operator view.

README.md

@@ -54,8 +54,25 @@ PYTHONPATH=src python3 -m phase_memory.cli store import --store .phase-memory-lo
 
 When installed, the package exposes the same commands as `phase-memory`.
 Commands emit JSON runtime envelopes by default and accept `--format summary`
-for a concise human-readable view. All current commands are dry-run planning
-operations; they do not mutate durable memory stores.
+for a concise human-readable view. Profile, graph, and store import/export
+commands are dry-run planning operations; they do not mutate durable memory
+stores by default.
+
+## Management Reports
+
+Inspect activity across every discovered phase-memory store (ops-warden
+coordination store, registry entries, and `PHASE_MEMORY_STORE_PATHS`):
+
+```bash
+phase-memory stores list --format summary
+phase-memory report --days 7 --format summary
+phase-memory report --store ops-warden-default --days 30
+make report-7d
+```
+
+Discovery honours `WARDEN_MEMORY_STORE`, `PHASE_MEMORY_REGISTRY`, and
+`PHASE_MEMORY_STORE_PATHS`. Reports are metadata-only and never include secret
+values.
 
 ## Local Runtime