fix(15): correct SQL column names in trend detector and alert evaluator

- Replace `collected_at` with `time` (actual hypertable column) in 5 queries
- Remove non-existent `rule_type` column from site_alert_events INSERTs
- Fix trend dedup query to use `rule_id IS NULL` instead of `rule_type`

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -38,7 +38,7 @@ v9.7 transforms TOD from a flat device list into a site-aware fleet management p
 - [x] **Phase 12: Per-Client Wireless Collection** - Poller extension to collect registration table and per-interface RF stats (completed 2026-03-19)
 - [x] **Phase 13: Link Discovery + Registration Ingestion** - Backend NATS consumer, MAC resolution, AP-CPE link state machine (completed 2026-03-19)
 - [x] **Phase 14: Site Dashboard + Sector Views + Wireless UI** - Site detail page, sector-centric view, per-station wireless tables (completed 2026-03-19)
-- [ ] **Phase 15: Signal Trending + Site Alerting** - Signal history charts, degradation detection, site/sector alert rules
+- [x] **Phase 15: Signal Trending + Site Alerting** - Signal history charts, degradation detection, site/sector alert rules (completed 2026-03-19)
 
 ## Phase Details
 
@@ -117,7 +117,7 @@ Plans:
   2. System detects and surfaces signal degradation trends (e.g., "signal dropped 8dB over 2 weeks")
   3. Operator can create site-scoped alert rules (e.g., "alert when >20% of devices at this site go offline")
   4. Operator can create sector-scoped alert rules (e.g., "alert when sector average signal drops below -75dBm")
-**Plans:** 2/3 plans executed
+**Plans:** 3/3 plans complete
 
 Plans:
 - [ ] 15-01-PLAN.md — Backend data model, services, and REST API for site alert rules, alert events, and signal history
@@ -131,7 +131,7 @@ Plans:
 | Sites | SITE-01, SITE-02, SITE-03, SITE-04, SITE-05, SITE-06 | 11 | 3/3 | Complete    | 2026-03-19 | DASH-01 | 11 | 1 |
 | Site Dashboard | DASH-02, DASH-03, DASH-04 | 14 | 3/3 | Complete    | 2026-03-19 | SECT-01, SECT-02, SECT-03 | 14 | 3 |
 | Wireless Collection | WRCL-01, WRCL-02, WRCL-03, WRCL-04, WRCL-05, WRCL-06 | 12 | 2/2 | Complete    | 2026-03-19 | LINK-01, LINK-02, LINK-03, LINK-04 | 13 | 3/3 | Complete    | 2026-03-19 | WRUI-01, WRUI-02, WRUI-03 | 14 | 3 |
-| Signal Trending | TRND-01, TRND-02 | 15 | 2/3 | In Progress|  | ALRT-01, ALRT-02 | 15 | 2 |
+| Signal Trending | TRND-01, TRND-02 | 15 | 3/3 | Complete   | 2026-03-19 | ALRT-01, ALRT-02 | 15 | 2 |
 | **Total** | | | **30** |
 
 ## Progress

.planning/STATE.md

@@ -3,13 +3,13 @@ gsd_state_version: 1.0
 milestone: v9.7
 milestone_name: Tower & Site Management
 status: unknown
-stopped_at: Completed 15-01-PLAN.md
+stopped_at: Completed 15-03-PLAN.md
-last_updated: "2026-03-19T12:19:31.850Z"
+last_updated: "2026-03-19T12:26:34.674Z"
 progress:
   total_phases: 5
-  completed_phases: 4
+  completed_phases: 5
   total_plans: 14
-  completed_plans: 13
+  completed_plans: 14
 ---
 
 # Project State
@@ -48,6 +48,7 @@ Plan: 2 of 3
 | Phase 14 P03 | 3min | 2 tasks | 6 files |
 | Phase 15 P02 | 3min | 2 tasks | 4 files |
 | Phase 15 P01 | 4min | 2 tasks | 10 files |
+| Phase 15 P03 | 5min | 3 tasks | 9 files |
 
 ## Accumulated Context
 
@@ -91,6 +92,9 @@ Decisions are logged in PROJECT.md Key Decisions table.
 - [Phase 15]: Site alert tables are separate from device-level alert_rules/alert_events (no coupling between systems)
 - [Phase 15]: Signal history uses TimescaleDB time_bucket with 3 range presets (5min/1h/4h buckets)
 - [Phase 15]: Alert event count endpoint returns simple JSON for notification bell badge
+- [Phase 15]: NotificationBell placed in ContextStrip for consistent header integration
+- [Phase 15]: Expandable chart rows use React.Fragment pattern with per-component state
+- [Phase 15]: Alert rule type selector is context-aware (sector types when sectorId provided, site types otherwise)
 
 ### Pending Todos
 
@@ -104,6 +108,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-19T12:19:31.847Z
+Last session: 2026-03-19T12:26:34.671Z
-Stopped at: Completed 15-01-PLAN.md
+Stopped at: Completed 15-03-PLAN.md
 Resume file: None

backend/app/services/alert_evaluator_site.py

@@ -72,7 +72,7 @@ async def _evaluate_condition(session, rule) -> bool:  # noqa: ANN001
                 FROM wireless_registrations wr
                 JOIN devices d ON d.id = wr.device_id
                 WHERE d.sector_id = :sector_id
-                  AND wr.collected_at > now() - interval '10 minutes'
+                  AND wr.time > now() - interval '10 minutes'
             """),
             {"sector_id": sector_id},
         )
@@ -93,7 +93,7 @@ async def _evaluate_condition(session, rule) -> bool:  # noqa: ANN001
                 FROM wireless_registrations wr
                 JOIN devices d ON d.id = wr.device_id
                 WHERE d.sector_id = :sector_id
-                  AND wr.collected_at > now() - interval '10 minutes'
+                  AND wr.time > now() - interval '10 minutes'
             """),
             {"sector_id": sector_id},
         )
@@ -106,7 +106,7 @@ async def _evaluate_condition(session, rule) -> bool:  # noqa: ANN001
                 FROM wireless_registrations wr
                 JOIN devices d ON d.id = wr.device_id
                 WHERE d.sector_id = :sector_id
-                  AND wr.collected_at BETWEEN now() - interval '70 minutes'
+                  AND wr.time BETWEEN now() - interval '70 minutes'
                                          AND now() - interval '60 minutes'
             """),
             {"sector_id": sector_id},
@@ -178,10 +178,10 @@ async def _evaluate_rules() -> None:
                     await session.execute(
                         text("""
                             INSERT INTO site_alert_events
-                                (tenant_id, site_id, sector_id, rule_id, rule_type,
+                                (tenant_id, site_id, sector_id, rule_id,
                                  severity, message, state, consecutive_hits, triggered_at)
                             VALUES
-                                (:tenant_id, :site_id, :sector_id, :rule_id, :rule_type,
+                                (:tenant_id, :site_id, :sector_id, :rule_id,
                                  :severity, :message, 'active', 1, now())
                         """),
                         {
@@ -189,7 +189,6 @@ async def _evaluate_rules() -> None:
                             "site_id": str(rule.site_id),
                             "sector_id": str(rule.sector_id) if rule.sector_id else None,
                             "rule_id": rule_id,
-                            "rule_type": rule.rule_type,
                             "severity": severity,
                             "message": f"Alert rule '{rule.name}' condition met",
                         },

backend/app/services/trend_detector.py

@@ -53,7 +53,7 @@ async def _detect_trends() -> None:
                     FROM wireless_registrations
                     WHERE mac_address = :mac
                       AND device_id = :ap_device_id
-                      AND collected_at > now() - interval '7 days'
+                      AND time > now() - interval '7 days'
                 """),
                 {"mac": mac, "ap_device_id": str(ap_device_id)},
             )
@@ -67,7 +67,7 @@ async def _detect_trends() -> None:
                     FROM wireless_registrations
                     WHERE mac_address = :mac
                       AND device_id = :ap_device_id
-                      AND collected_at > now() - interval '14 days'
+                      AND time > now() - interval '14 days'
                 """),
                 {"mac": mac, "ap_device_id": str(ap_device_id)},
             )
@@ -88,7 +88,7 @@ async def _detect_trends() -> None:
                 text("""
                     SELECT id FROM site_alert_events
                     WHERE link_id = :link_id
-                      AND rule_type = 'signal_degradation'
+                      AND rule_id IS NULL
                       AND state = 'active'
                     LIMIT 1
                 """),
@@ -105,10 +105,10 @@ async def _detect_trends() -> None:
                 await session.execute(
                     text("""
                         INSERT INTO site_alert_events
-                            (tenant_id, site_id, link_id, rule_type, severity, message, state,
+                            (tenant_id, site_id, link_id, severity, message, state,
                              consecutive_hits, triggered_at)
                         VALUES
-                            (:tenant_id, :site_id, :link_id, 'signal_degradation', 'warning',
+                            (:tenant_id, :site_id, :link_id, 'warning',
                              :message, 'active', 1, now())
                     """),
                     {