feat: Add pipeline execution UI, stage metrics, and API proxy routes

- Add run pipeline page with job selection UI
- Add execution detail page with stage metrics visualization
- Add stage_metrics and total_duration_ms to pipeline.executions table
- Create Next.js API proxy routes for all pipeline endpoints
- Fix trailing slash issues in pipeline-api.ts URLs
- Add Docker volume mounts for pipeline packages
- Add REVIEWIQ_DATABASE_URL and LLM API keys to docker-compose
- Fix JSONB field parsing in execution detail endpoint

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

migrations/versions/007_add_stage_metrics.sql

@@ -0,0 +1,36 @@
+-- =============================================================================
+-- Migration: 007_add_stage_metrics.sql
+-- Add stage-level metrics to pipeline executions
+-- =============================================================================
+--
+-- Adds a JSONB column to store per-stage execution metrics for profiling:
+--   - duration_ms: execution time per stage
+--   - records_processed: number of records handled
+--   - errors: any stage-specific errors
+--
+-- Date: 2026-01-24
+-- =============================================================================
+
+-- Add stage_metrics column to store per-stage profiling data
+ALTER TABLE pipeline.executions
+ADD COLUMN IF NOT EXISTS stage_metrics JSONB;
+
+COMMENT ON COLUMN pipeline.executions.stage_metrics IS 'Per-stage execution metrics (timing, records processed, errors)';
+
+-- Example structure:
+-- {
+--   "normalize": {"duration_ms": 150, "records_in": 100, "records_out": 100, "success": true},
+--   "classify": {"duration_ms": 2500, "records_in": 100, "records_out": 100, "success": true},
+--   "route": {"duration_ms": 80, "records_in": 100, "records_out": 15, "success": true},
+--   "aggregate": {"duration_ms": 45, "records_in": 100, "records_out": 1, "success": true}
+-- }
+
+-- Add total_duration_ms for quick access to overall execution time
+ALTER TABLE pipeline.executions
+ADD COLUMN IF NOT EXISTS total_duration_ms INTEGER;
+
+COMMENT ON COLUMN pipeline.executions.total_duration_ms IS 'Total execution duration in milliseconds';
+
+-- =============================================================================
+-- DONE
+-- =============================================================================