feat(brands): Add calculated tags with configurable thresholds

Tags assigned per store:
- must_win: High-revenue store with room to grow SKUs
- at_risk: High OOS% (losing shelf presence)
- top_performer: High sales + good inventory management
- growth: Above-average velocity
- low_inventory: Low days on hand

Configurable via query params:
- ?must_win_max_skus=5
- ?at_risk_oos_pct=30
- ?top_performer_max_oos=15
- ?low_inventory_days=7

Response includes tag_thresholds showing applied values.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/src/routes/brands.ts

@@ -713,6 +713,14 @@ export function createBrandsRouter(pool: Pool): Router {
       // Margin assumption - default 50% (industry standard)
       const marginPct = Math.min(Math.max(parseFloat(req.query.margin_pct as string) || 50, 0), 100);
 
+      // Configurable tag thresholds (Cannabrands can set their own basis)
+      const tagConfig = {
+        must_win_max_skus: parseInt(req.query.must_win_max_skus as string) || 5,
+        at_risk_oos_pct: parseInt(req.query.at_risk_oos_pct as string) || 30,
+        top_performer_max_oos: parseInt(req.query.top_performer_max_oos as string) || 15,
+        low_inventory_days: parseInt(req.query.low_inventory_days as string) || 7,
+      };
+
       const startDate = new Date();
       startDate.setDate(startDate.getDate() - days);
 
@@ -877,11 +885,71 @@ export function createBrandsRouter(pool: Pool): Router {
 
       const totals = totalsResult.rows[0] || {};
 
+      // Calculate percentiles for relative tagging
+      const salesValues = result.rows
+        .map(r => r.total_sales_est ? parseFloat(r.total_sales_est) : 0)
+        .sort((a, b) => a - b);
+      const velocityValues = result.rows
+        .map(r => r.avg_daily_units ? parseFloat(r.avg_daily_units) : 0)
+        .sort((a, b) => a - b);
+
+      const getPercentile = (arr: number[], p: number) => {
+        if (arr.length === 0) return 0;
+        const idx = Math.floor(arr.length * p);
+        return arr[Math.min(idx, arr.length - 1)];
+      };
+
+      const salesP75 = getPercentile(salesValues, 0.75);
+      const salesP50 = getPercentile(salesValues, 0.50);
+      const velocityP75 = getPercentile(velocityValues, 0.75);
+
+      // Tag calculation function (uses configurable thresholds)
+      const calculateTags = (row: any): string[] => {
+        const tags: string[] = [];
+        const sales = row.total_sales_est ? parseFloat(row.total_sales_est) : 0;
+        const velocity = row.avg_daily_units ? parseFloat(row.avg_daily_units) : 0;
+        const oosPct = parseInt(row.oos_pct) || 0;
+        const skuCount = parseInt(row.active_skus) || 0;
+        const daysOnHand = row.avg_days_on_hand ? parseFloat(row.avg_days_on_hand) : null;
+
+        // Must Win: High-revenue store where brand has room to grow
+        // Configurable: ?must_win_max_skus=5 (default)
+        if (sales >= salesP75 && skuCount < tagConfig.must_win_max_skus) {
+          tags.push('must_win');
+        }
+
+        // At Risk: High OOS% means brand is losing shelf presence
+        // Configurable: ?at_risk_oos_pct=30 (default)
+        if (oosPct >= tagConfig.at_risk_oos_pct) {
+          tags.push('at_risk');
+        }
+
+        // Top Performer: High sales + good inventory management
+        // Configurable: ?top_performer_max_oos=15 (default)
+        if (sales >= salesP75 && oosPct < tagConfig.top_performer_max_oos) {
+          tags.push('top_performer');
+        }
+
+        // Growth: Above-average velocity - momentum store
+        if (velocity >= velocityP75 && sales >= salesP50) {
+          tags.push('growth');
+        }
+
+        // Low Inventory: Days on hand below threshold
+        // Configurable: ?low_inventory_days=7 (default)
+        if (daysOnHand !== null && daysOnHand < tagConfig.low_inventory_days && daysOnHand > 0) {
+          tags.push('low_inventory');
+        }
+
+        return tags;
+      };
+
       res.json({
         brand: brandName,
         period_days: days,
         state: stateCode || 'all',
         margin_pct_assumed: marginPct,
+        tag_thresholds: tagConfig,
         summary: {
           total_stores: parseInt(totals.total_stores) || 0,
           total_oos: parseInt(totals.total_oos) || 0,
@@ -889,12 +957,15 @@ export function createBrandsRouter(pool: Pool): Router {
         stores: result.rows.map(row => {
           const totalSalesEst = row.total_sales_est ? parseFloat(row.total_sales_est) : null;
           const marginEst = totalSalesEst ? totalSalesEst * (marginPct / 100) : null;
+          const tags = calculateTags(row);
           return {
           store_id: row.store_id,
           store_name: row.store_name,
           state_code: row.state_code,
           city: row.city,
           address: row.address,
+          // Tags (calculated)
+          tags,
           // SKU counts
           active_skus: parseInt(row.active_skus) || 0,
           oos_skus: parseInt(row.oos_skus) || 0,