perf(api): eliminate 3 N+1 query patterns

- timeline-holiday-load-support: deduplicate getResolvedCalendarHolidays
  by location key so resources sharing the same country/state/city resolve
  holidays once instead of per-resource
- rate-card-lookup: add lookupRatesBatch that loads rate card lines once
  and scores locally per demand line, replacing per-line DB round-trips
  in estimate-demand-lines autoFillDemandLineRates
- config-readmodels: include _count in utilization-category list query
  instead of calling getById per category for project counts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/api/src/router/estimate-demand-lines.ts

@@ -1,11 +1,9 @@
 import { normalizeEstimateDemandLine, summarizeEstimateDemandLines } from "@capakraken/engine";
 import { CreateEstimateSchema } from "@capakraken/shared";
 import { z } from "zod";
-import { lookupRate } from "../lib/rate-card-lookup.js";
+import { lookupRatesBatch } from "../lib/rate-card-lookup.js";
 
-function buildComputedMetrics(
-  demandLines: z.infer<typeof CreateEstimateSchema>["demandLines"],
-) {
+function buildComputedMetrics(demandLines: z.infer<typeof CreateEstimateSchema>["demandLines"]) {
   const summary = summarizeEstimateDemandLines(demandLines);
 
   return [
@@ -62,7 +60,9 @@ function normalizeDemandLines<
   const snapshotsByResourceId = new Map(
     input.resourceSnapshots
       .filter(
-        (snapshot): snapshot is (typeof input.resourceSnapshots)[number] & {
+        (
+          snapshot,
+        ): snapshot is (typeof input.resourceSnapshots)[number] & {
           resourceId: string;
         } => typeof snapshot.resourceId === "string" && snapshot.resourceId.length > 0,
       )
@@ -71,8 +71,7 @@ function normalizeDemandLines<
 
   return input.demandLines.map((line) =>
     normalizeEstimateDemandLine(line, {
-      resourceSnapshot:
-        line.resourceId != null ? snapshotsByResourceId.get(line.resourceId) : null,
+      resourceSnapshot: line.resourceId != null ? snapshotsByResourceId.get(line.resourceId) : null,
       defaultCurrency: baseCurrency,
     }),
   );
@@ -117,44 +116,60 @@ export async function autoFillDemandLineRates(
     clientId = project?.clientId ?? null;
   }
 
-  const autoFilledIndices: number[] = [];
-  const enriched = await Promise.all(
-    demandLines.map(async (line, index) => {
-      const isDefaultRate = line.costRateCents === 0 && line.billRateCents === 0;
-      const hasExplicitSource = line.rateSource != null && line.rateSource.length > 0;
-      if (!isDefaultRate || hasExplicitSource) {
-        return line;
-      }
-
-      const result = await lookupRate(db, {
-        clientId,
-        chapter: line.chapter ?? null,
-        roleId: line.roleId ?? null,
+  // Identify which lines need auto-fill and collect their lookup params
+  const needsLookup: {
+    index: number;
+    params: { chapter: string | null; roleId: string | null };
+  }[] = [];
+  for (let i = 0; i < demandLines.length; i++) {
+    const line = demandLines[i]!;
+    const isDefaultRate = line.costRateCents === 0 && line.billRateCents === 0;
+    const hasExplicitSource = line.rateSource != null && line.rateSource.length > 0;
+    if (isDefaultRate && !hasExplicitSource) {
+      needsLookup.push({
+        index: i,
+        params: { chapter: line.chapter ?? null, roleId: line.roleId ?? null },
       });
-      if (!result) {
-        return line;
-      }
+    }
+  }
 
-      autoFilledIndices.push(index);
-      const existingMetadata = (line.metadata ?? {}) as Record<string, unknown>;
-      return {
-        ...line,
-        costRateCents: result.costRateCents,
-        billRateCents: result.billRateCents,
-        currency: result.currency,
-        rateSource: `rate-card:${result.rateCardId}`,
-        metadata: {
-          ...existingMetadata,
-          autoAppliedRateCard: {
-            rateCardId: result.rateCardId,
-            rateCardLineId: result.rateCardLineId,
-            rateCardName: result.rateCardName,
-            appliedAt: new Date().toISOString(),
-          },
-        },
-      };
-    }),
+  if (needsLookup.length === 0) {
+    return { demandLines, autoFilledIndices: [] };
+  }
+
+  // Single DB query for all rate card lines, scored locally per demand line
+  const results = await lookupRatesBatch(
+    db,
+    clientId,
+    needsLookup.map((entry) => entry.params),
   );
 
+  const autoFilledIndices: number[] = [];
+  const enriched = [...demandLines];
+  for (let i = 0; i < needsLookup.length; i++) {
+    const result = results[i];
+    if (!result) continue;
+    const { index } = needsLookup[i]!;
+    autoFilledIndices.push(index);
+    const line = demandLines[index]!;
+    const existingMetadata = (line.metadata ?? {}) as Record<string, unknown>;
+    enriched[index] = {
+      ...line,
+      costRateCents: result.costRateCents,
+      billRateCents: result.billRateCents,
+      currency: result.currency,
+      rateSource: `rate-card:${result.rateCardId}`,
+      metadata: {
+        ...existingMetadata,
+        autoAppliedRateCard: {
+          rateCardId: result.rateCardId,
+          rateCardLineId: result.rateCardLineId,
+          rateCardName: result.rateCardName,
+          appliedAt: new Date().toISOString(),
+        },
+      },
+    };
+  }
+
   return { demandLines: enriched, autoFilledIndices };
 }