feat(gateway): add system.sessionAnalytics usage snapshot RPC

docs/api/PROTOCOL.md

@@ -303,6 +303,42 @@ Online/offline is inferred from inactivity threshold in the daemon.
 }
 ```
 
+#### `system.sessionAnalytics`
+
+Return aggregate session analytics from the SQLite message history.
+
+Useful for operator dashboards and trend checks (sessions/day, message volume, top active sessions).
+
+**Request:**
+```json
+{
+  "id": 10,
+  "method": "system.sessionAnalytics",
+  "params": {
+    "days": 30,
+    "topLimit": 10
+  }
+}
+```
+
+**Response:**
+```json
+{
+  "id": 10,
+  "result": {
+    "daily": [
+      { "day": "2026-02-16", "sessions": 14, "messages": 228 }
+    ],
+    "topSessions": [
+      { "sessionId": "telegram:123456", "messages": 42, "lastActivity": 1739700300 }
+    ],
+    "averageMessagesPerSession": 16.29,
+    "totalSessions": 14,
+    "totalMessages": 228
+  }
+}
+```
+
 **Response:**
 ```json
 {

docs/plans/state.json

@@ -7,7 +7,7 @@
       "status": "completed",
       "date": "2026-02-16",
       "updated": "2026-02-16",
-      "summary": "Added first-class automation presets and scheduling upgrades: `automation.daily_briefing` now auto-registers an opinionated cron job for morning briefings, and backup scheduling now supports cron expressions via `backup.schedule` plus optional `backup.run_on_start` while preserving interval fallback. Added `BackupScheduler` with `backup.notify` channel alerts, configurable `backup.failure_threshold`, and recovery notifications (`backup.notify_recovery`) so backup failures/recoveries proactively notify operators. Extended heartbeat monitoring with `process_memory`, `backup`, and `provider_errors` checks (with thresholds) so high RSS usage, backup failure streaks, and model-provider error spikes proactively trigger health alerts. Added timezone-safe daily briefing dedupe via `automation.daily_briefing.dedupe_per_local_day` and cron-level `once_per_local_day` so morning briefings do not send twice on the same local day. Added `minio.share` tool to upload local artifacts and return temporary MinIO share links using existing backup MinIO credentials.",
+      "summary": "Added first-class automation presets and scheduling upgrades: `automation.daily_briefing` now auto-registers an opinionated cron job for morning briefings, and backup scheduling now supports cron expressions via `backup.schedule` plus optional `backup.run_on_start` while preserving interval fallback. Added `BackupScheduler` with `backup.notify` channel alerts, configurable `backup.failure_threshold`, and recovery notifications (`backup.notify_recovery`) so backup failures/recoveries proactively notify operators. Extended heartbeat monitoring with `process_memory`, `backup`, and `provider_errors` checks (with thresholds) so high RSS usage, backup failure streaks, and model-provider error spikes proactively trigger health alerts. Added timezone-safe daily briefing dedupe via `automation.daily_briefing.dedupe_per_local_day` and cron-level `once_per_local_day` so morning briefings do not send twice on the same local day. Added `minio.share` tool to upload local artifacts and return temporary MinIO share links using existing backup MinIO credentials. Added `system.sessionAnalytics` RPC with SQLite-backed aggregates (daily sessions/messages, average messages per session, top active sessions) for operator usage tracking.",
       "files_modified": [
         "src/config/schema.ts",
         "src/config/schema.test.ts",
@@ -28,6 +28,13 @@
         "src/tools/builtin/index.ts",
         "src/tools/index.ts",
         "src/tools/policy.ts",
+        "src/session/store.ts",
+        "src/session/store.test.ts",
+        "src/session/manager.ts",
+        "src/session/index.ts",
+        "src/gateway/handlers/system.ts",
+        "src/gateway/handlers/handlers.test.ts",
+        "src/gateway/server.ts",
         "src/daemon/channels.ts",
         "src/daemon/channels.test.ts",
         "src/daemon/index.ts",
@@ -35,10 +42,11 @@
         "src/gateway/handlers/services.ts",
         "src/gateway/handlers/services.test.ts",
         "src/tools/builtin/cron.ts",
+        "docs/api/PROTOCOL.md",
         "config/default.yaml",
         "README.md"
       ],
-      "test_status": "pnpm test:run src/automation/presets.test.ts src/automation/cron.test.ts src/automation/heartbeat.test.ts src/backup/scheduler.test.ts src/backup/status.test.ts src/tools/builtin/minio-share.test.ts src/tools/policy.test.ts src/config/schema.test.ts src/daemon/channels.test.ts src/gateway/handlers/services.test.ts + pnpm typecheck passing"
+      "test_status": "pnpm test:run src/automation/presets.test.ts src/automation/cron.test.ts src/automation/heartbeat.test.ts src/backup/scheduler.test.ts src/backup/status.test.ts src/tools/builtin/minio-share.test.ts src/tools/policy.test.ts src/config/schema.test.ts src/daemon/channels.test.ts src/gateway/handlers/services.test.ts src/session/store.test.ts src/gateway/handlers/handlers.test.ts + pnpm typecheck passing"
     },
     "backup-session-summary-audit-trail": {
       "status": "completed",
@@ -3324,7 +3332,7 @@
     }
   },
   "overall_progress": {
-    "total_test_count": 1848,
+    "total_test_count": 1851,
     "all_tests_passing": true,
     "p0_completion": "3/3 (100%)",
     "p1_completion": "4/4 (100%)",