feat(T4.1-T4.4): implement advanced operations & analytics (part 1)

T4.1: Real-time Metrics Dashboard
- Add internal/dashboard package with MetricsAggregator
- Record, aggregate, and query metrics
- Percentile calculations (p50, p95, p99)
- Time-series data with max size eviction
- 13 metrics tests, all passing

T4.2: Workflow Visualization & DAG Rendering
- Add internal/visualization package with DAGRenderer
- Convert dependency graphs to DOT format
- Critical path highlighting
- Topological sorting with parallel task detection
- HTML rendering for visualization
- 11 DAG rendering tests, all passing

T4.3: Advanced Search & Filtering
- Add internal/search package with WorkflowSearch
- Full-text indexing with word-based lookup
- Filter by status, assignee, tag, date range
- Regex pattern matching
- Saved filters for reusable queries
- 15 search tests, all passing

T4.4: Cost Tracking & Optimization
- Add internal/cost package with CostTracker
- Track LLM API costs (by token)
- Track git operation costs
- Track compute resource costs (by duration)
- Cost aggregation by workflow/type
- Optimization recommendations
- 11 cost tests, all passing

Total T4.1-T4.4: 50 tests passing
Next: T4.5-T4.8 (alerting, profiling, multi-cluster, self-deployment)

tasks/board-T4.md

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+# T4: Advanced Operations & Analytics
+
+## Overview
+Advanced operational capabilities for monitoring, visualization, cost optimization, and multi-cluster orchestration. Builds on T1-T3 foundation to enable enterprise-scale deployment.
+
+## Tasks
+
+| Task | Description | Tests | Status |
+|------|-------------|-------|--------|
+| T4.1 | Real-time metrics dashboard: queryable Prometheus metrics with aggregation | [ ] | 🔜 TODO |
+| T4.2 | Workflow visualization & DAG rendering: browser-based workflow inspector | [ ] | 🔜 TODO |
+| T4.3 | Advanced search & filtering: Elasticsearch-like task/workflow search | [ ] | 🔜 TODO |
+| T4.4 | Cost tracking & optimization: LLM API, git push, compute resource costs | [ ] | 🔜 TODO |
+| T4.5 | Automated alerting & anomaly detection: threshold rules, ML-based anomalies | [ ] | 🔜 TODO |
+| T4.6 | Workflow profiling & bottleneck analysis: identify slowest tasks | [ ] | 🔜 TODO |
+| T4.7 | Multi-cluster orchestration: deploy orchestrators across K8s clusters | [ ] | 🔜 TODO |
+| T4.8 | Self-deployment: orchestrator deploys itself (meta!) | [ ] | 🔜 TODO |
+
+---
+
+## Implementation Plan
+
+### T4.1: Real-time Metrics Dashboard
+- `internal/dashboard/metrics_aggregator.go` - Query Prometheus for metrics
+- `internal/dashboard/metrics_aggregator_test.go` - 15 tests
+- Features:
+  - Aggregate gauge/counter/histogram metrics
+  - Time-range queries
+  - Percentile calculations (p50, p95, p99)
+  - Error rate aggregation
+  - Throughput calculations
+
+### T4.2: Workflow Visualization
+- `internal/visualization/dag_renderer.go` - DAG graph generation
+- `internal/visualization/dag_renderer_test.go` - 12 tests
+- Features:
+  - Convert dependency graph to DOT format
+  - SVG/PNG rendering capability
+  - Task status coloring
+  - Critical path highlighting
+  - Parallel task grouping
+
+### T4.3: Advanced Search & Filtering
+- `internal/search/workflow_search.go` - Full-text search
+- `internal/search/workflow_search_test.go` - 18 tests
+- Features:
+  - Index workflows by content
+  - Filter by status, date, assignee
+  - Full-text search on task descriptions
+  - Regex pattern matching
+  - Saved filters
+
+### T4.4: Cost Tracking & Optimization
+- `internal/cost/cost_tracker.go` - Track compute/API costs
+- `internal/cost/cost_tracker_test.go` - 16 tests
+- Features:
+  - LLM API call costs (tokens × price)
+  - Git push operation costs
+  - K8s compute resource costs
+  - Cost per workflow
+  - Cost optimization recommendations
+
+### T4.5: Automated Alerting & Anomaly Detection
+- `internal/alerting/alert_manager.go` - Rule-based alerts
+- `internal/alerting/alert_manager_test.go` - 20 tests
+- Features:
+  - Threshold-based alerts
+  - Pattern-based anomaly detection
+  - Alert routing (email, Slack, PagerDuty)
+  - Alert history
+  - Deduplication
+
+### T4.6: Workflow Profiling & Bottleneck Analysis
+- `internal/profiling/workflow_profiler.go` - Identify slow tasks
+- `internal/profiling/workflow_profiler_test.go` - 17 tests
+- Features:
+  - Per-task execution time breakdown
+  - Critical path identification
+  - Parallel vs sequential timing
+  - Resource utilization per task
+  - Optimization suggestions
+
+### T4.7: Multi-cluster Orchestration
+- `internal/clusters/cluster_manager.go` - Manage multiple K8s clusters
+- `internal/clusters/cluster_manager_test.go` - 19 tests
+- Features:
+  - Register/discover clusters
+  - Route workflows to clusters
+  - Cross-cluster task coordination
+  - Cluster health monitoring
+  - Failover support
+
+### T4.8: Self-Deployment
+- `internal/deployment/self_deployer.go` - Orchestrator deploys itself
+- `internal/deployment/self_deployer_test.go` - 14 tests
+- Features:
+  - Build orchestrator container
+  - Generate K8s manifests
+  - Deploy new version
+  - Health check & rollback
+  - Version management
+
+---
+
+## Test Coverage Target
+- T4 Total: **131+ tests** (similar to T3)
+- All packages: 100% test pass rate
+- Performance benchmarks included
+
+---
+
+## Success Criteria
+✅ All 8 T4 tasks complete
+✅ 131+ tests passing
+✅ Dashboard queryable in real-time
+✅ DAG visualization renders workflow dependencies
+✅ Cost tracking shows savings from T2 optimizations
+✅ Anomaly detection catches performance regressions
+✅ Multi-cluster deployment supported
+✅ Orchestrator can self-deploy
+
+---
+
+## Timeline
+- T4.1-T4.4: Week 1 (implementation + tests)
+- T4.5-T4.8: Week 2 (implementation + tests)
+- Integration testing: Week 3
+- Production deployment: Week 4