docs: update README, runbook, and steering files for today's changes

- README: added AI agent management section, updated paper trading
  description (no manual capital controls, broker-synced reset)
- Steering: migration numbers updated to 027 (next: 028), added
  trading engine endpoint, ruff pinning and isort config notes
- Runbook: already had reset/Alpaca sections from earlier commits

.kiro/steering/project-context.md

@@ -25,6 +25,7 @@ Three-layer signal aggregation engine:
 - Dashboard: `https://stonks.celestium.life`
 - Query API: `https://stonks-api.celestium.life`
 - Symbol Registry: `https://stonks-registry.celestium.life`
+- Trading Engine: `https://stonks-trading.celestium.life`
 - Superset: `https://stonks-dash.celestium.life`
 - Trino: `https://stonks-trino.celestium.life`
 
@@ -72,12 +73,15 @@ When a full reset is needed:
 - Ollama: `ollama.ollama-service.svc.cluster.local:11434` (cluster-internal), also at `http://10.1.1.12:2701` (external), GPU: 4070 Ti Super 16GB
 
 ## Database Migrations
-- Located in `infra/migrations/001_*.sql` through `017_*.sql`
+- Located in `infra/migrations/001_*.sql` through `027_*.sql`
 - Applied automatically by `runmefirst.sh` in sorted order
-- Next migration number: **018**
+- Next migration number: **028**
 - Key migrations:
   - 016: Global news interpolation (global_events, macro_impact_records, exposure_profiles, trend_projections)
   - 017: Competitive intelligence (competitor_relationships, competitive_signal_records)
+  - 024: Trend history time-series table
+  - 026: AI agents management (ai_agents, agent_performance_log)
+  - 027: Agent variants (agent_variants table for A/B testing)
 
 ## Key Conventions
 - All services use `services/shared/config.py` for configuration via env vars