Add CCP Metrics page with multi-vertical VCL upload and cross-org reporting

New feature: multi-file per-vertical compliance xlsx upload with scoped
resolution logic, executive-level aggregated reporting, and drill-down
by vertical and metric. Supports daily upload cadence and batch commit.

Backend:
- Migration: add vertical column to compliance_items/uploads, create
  vcl_multi_vertical_summary table
- New route module: routes/vclMultiVertical.js with preview, commit,
  stats, trend, metric drill-down, device list, and burndown endpoints
- New helpers: parseVerticalFilename(), computeVerticalBurndown()
- Vertical-scoped resolution: uploading one vertical never resolves
  items from other verticals

Frontend:
- CCPMetricsPage with stats bar, trend chart, donut, vertical table
- Drill-down: vertical -> metrics by category -> device list
- Per-vertical burndown forecast chart
- MultiVerticalUploadModal: multi-file drag-drop, batch preview, commit
- Nav entry: CCP Metrics (Building2 icon)

Docs:
- Design brief for stakeholder meeting (docs/vcl-multi-vertical-design-brief.md)

backend/migrations/run-all.js

@@ -19,6 +19,7 @@ const POSTGRES_MIGRATIONS = [
     'add_fp_submissions_requeued_at.js',
     'add_vcl_reporting_columns.js',
     'add_vcl_vertical_metadata.js',
+    'add_vcl_multi_vertical.js',
 ];
 
 async function runAll() {