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/helpers/vclHelpers.js

@@ -205,6 +205,79 @@ function mapColumnHeaders(headers) {
     return mapping;
 }
 
+/**
+ * Extracts vertical code and report date from a filename.
+ * Pattern: <VERTICAL>_YYYY_MM_DD.xlsx
+ * The vertical is everything before the trailing _YYYY_MM_DD portion.
+ *
+ * Examples:
+ *   NTS_AEO_2026_05_11.xlsx    → { vertical: 'NTS_AEO', date: '2026-05-11' }
+ *   SDIT_CISO_2026_05_11.xlsx  → { vertical: 'SDIT_CISO', date: '2026-05-11' }
+ *   SR_2026_05_11.xlsx         → { vertical: 'SR', date: '2026-05-11' }
+ *   AllOthers_2026_05_11.xlsx  → { vertical: 'AllOthers', date: '2026-05-11' }
+ *
+ * Returns null if the filename does not match the expected pattern.
+ */
+function parseVerticalFilename(filename) {
+    // Strip .xlsx extension (case-insensitive)
+    const stem = filename.replace(/\.xlsx$/i, '');
+    // Match: everything up to the last _YYYY_MM_DD
+    const match = stem.match(/^(.+?)_(\d{4})_(\d{2})_(\d{2})$/);
+    if (!match) return null;
+
+    const vertical = match[1];
+    const date = `${match[2]}-${match[3]}-${match[4]}`;
+
+    // Validate the date portion is a real date
+    if (!isValidDateString(date)) return null;
+
+    return { vertical, date };
+}
+
+/**
+ * Computes per-vertical burndown forecast from non-compliant items.
+ * Returns breakdown of items with/without resolution dates and monthly projections.
+ */
+function computeVerticalBurndown(items) {
+    const total = items.length;
+    const withDates = items.filter(i => i.resolution_date != null);
+    const blockers = items.filter(i => i.resolution_date == null);
+
+    // Bucket by month
+    const monthly = {};
+    for (const item of withDates) {
+        const dateStr = typeof item.resolution_date === 'string'
+            ? item.resolution_date
+            : item.resolution_date.toISOString().slice(0, 10);
+        const month = dateStr.slice(0, 7); // YYYY-MM
+        monthly[month] = (monthly[month] || 0) + 1;
+    }
+
+    // Cumulative projection — how many remain after each month
+    let remaining = total;
+    const projection = {};
+    for (const month of Object.keys(monthly).sort()) {
+        remaining -= monthly[month];
+        projection[month] = { remediated: monthly[month], remaining };
+    }
+
+    // Projected clear date — first month where remaining hits 0 (excluding blockers)
+    let projectedClearDate = null;
+    if (blockers.length === 0 && Object.keys(projection).length > 0) {
+        const sortedMonths = Object.keys(projection).sort();
+        projectedClearDate = sortedMonths[sortedMonths.length - 1];
+    }
+
+    return {
+        total,
+        blockers: blockers.length,
+        with_dates: withDates.length,
+        monthly,
+        projection,
+        projected_clear_date: projectedClearDate,
+    };
+}
+
 module.exports = {
     truncateText,
     validateRemediationPlan,
@@ -217,4 +290,6 @@ module.exports = {
     matchByHostname,
     computeBulkDiff,
     mapColumnHeaders,
+    parseVerticalFilename,
+    computeVerticalBurndown,
 };