feat(analytics): Brand promotional history + specials fix + API key editing

- Add brand promotional history endpoint (GET /api/analytics/v2/brand/:name/promotions)
  - Tracks when products go on special, duration, discounts, quantity sold estimates
  - Aggregates by category with frequency metrics (weekly/monthly)
- Add quantity changes endpoint (GET /api/analytics/v2/store/:id/quantity-changes)
  - Filter by direction (increase/decrease/all) for sales vs restock estimation
- Fix canonical-upsert to populate stock_quantity and total_quantity_available
- Add API key edit functionality in admin UI
  - Edit allowed domains and IPs
  - Display domains in list view

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

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

backend/src/services/analytics/StoreAnalyticsService.ts

@@ -259,6 +259,122 @@ export class StoreAnalyticsService {
     }));
   }
 
+  /**
+   * Get quantity changes for a store (increases/decreases)
+   * Useful for estimating sales (decreases) or restocks (increases)
+   *
+   * @param direction - 'decrease' for likely sales, 'increase' for restocks, 'all' for both
+   */
+  async getQuantityChanges(
+    dispensaryId: number,
+    options: {
+      window?: TimeWindow;
+      customRange?: DateRange;
+      direction?: 'increase' | 'decrease' | 'all';
+      limit?: number;
+    } = {}
+  ): Promise<{
+    dispensary_id: number;
+    window: TimeWindow;
+    direction: string;
+    total_changes: number;
+    total_units_decreased: number;
+    total_units_increased: number;
+    changes: Array<{
+      store_product_id: number;
+      product_name: string;
+      brand_name: string | null;
+      category: string | null;
+      old_quantity: number;
+      new_quantity: number;
+      quantity_delta: number;
+      direction: 'increase' | 'decrease';
+      captured_at: string;
+    }>;
+  }> {
+    const { window = '7d', customRange, direction = 'all', limit = 100 } = options;
+    const { start, end } = getDateRangeFromWindow(window, customRange);
+
+    // Build direction filter
+    let directionFilter = '';
+    if (direction === 'decrease') {
+      directionFilter = 'AND qty_delta < 0';
+    } else if (direction === 'increase') {
+      directionFilter = 'AND qty_delta > 0';
+    }
+
+    const result = await this.pool.query(`
+      WITH qty_changes AS (
+        SELECT
+          sps.store_product_id,
+          sp.name_raw AS product_name,
+          sp.brand_name_raw AS brand_name,
+          sp.category_raw AS category,
+          LAG(sps.stock_quantity) OVER w AS old_quantity,
+          sps.stock_quantity AS new_quantity,
+          sps.stock_quantity - LAG(sps.stock_quantity) OVER w AS qty_delta,
+          sps.captured_at
+        FROM store_product_snapshots sps
+        JOIN store_products sp ON sp.id = sps.store_product_id
+        WHERE sps.dispensary_id = $1
+          AND sps.captured_at >= $2
+          AND sps.captured_at <= $3
+          AND sps.stock_quantity IS NOT NULL
+        WINDOW w AS (PARTITION BY sps.store_product_id ORDER BY sps.captured_at)
+      )
+      SELECT *
+      FROM qty_changes
+      WHERE old_quantity IS NOT NULL
+        AND qty_delta != 0
+        ${directionFilter}
+      ORDER BY captured_at DESC
+      LIMIT $4
+    `, [dispensaryId, start, end, limit]);
+
+    // Calculate totals
+    const totalsResult = await this.pool.query(`
+      WITH qty_changes AS (
+        SELECT
+          sps.stock_quantity - LAG(sps.stock_quantity) OVER w AS qty_delta
+        FROM store_product_snapshots sps
+        WHERE sps.dispensary_id = $1
+          AND sps.captured_at >= $2
+          AND sps.captured_at <= $3
+          AND sps.stock_quantity IS NOT NULL
+          AND sps.store_product_id IS NOT NULL
+        WINDOW w AS (PARTITION BY sps.store_product_id ORDER BY sps.captured_at)
+      )
+      SELECT
+        COUNT(*) FILTER (WHERE qty_delta != 0) AS total_changes,
+        COALESCE(SUM(ABS(qty_delta)) FILTER (WHERE qty_delta < 0), 0) AS units_decreased,
+        COALESCE(SUM(qty_delta) FILTER (WHERE qty_delta > 0), 0) AS units_increased
+      FROM qty_changes
+      WHERE qty_delta IS NOT NULL
+    `, [dispensaryId, start, end]);
+
+    const totals = totalsResult.rows[0] || {};
+
+    return {
+      dispensary_id: dispensaryId,
+      window,
+      direction,
+      total_changes: parseInt(totals.total_changes) || 0,
+      total_units_decreased: parseInt(totals.units_decreased) || 0,
+      total_units_increased: parseInt(totals.units_increased) || 0,
+      changes: result.rows.map((row: any) => ({
+        store_product_id: row.store_product_id,
+        product_name: row.product_name,
+        brand_name: row.brand_name,
+        category: row.category,
+        old_quantity: row.old_quantity,
+        new_quantity: row.new_quantity,
+        quantity_delta: row.qty_delta,
+        direction: row.qty_delta > 0 ? 'increase' : 'decrease',
+        captured_at: row.captured_at?.toISOString() || null,
+      })),
+    };
+  }
+
   /**
    * Get store inventory composition (categories and brands breakdown)
    */