Consolidate server utilities into shared module

- Add lib/server/utils/normalize.ts with normalizeTicker, normalizeTagsOrNull, nowIso, todayIso
- Add lib/server/utils/validation.ts with asRecord, asBoolean, asStringArray, asEnum
- Add lib/server/utils/index.ts re-exporting all utilities
- Remove duplicate lib/server/utils.ts (old file)
- Update all repos and files to use shared utilities
- Remove redundant ?? '' from normalizeTicker calls
- Update watchlist.ts to use normalizeTagsOrNull for null-return tags

lib/server/repos/holdings.ts

@@ -3,6 +3,7 @@ import type { Holding } from '@/lib/types';
 import { recalculateHolding } from '@/lib/server/portfolio';
 import { db } from '@/lib/server/db';
 import { filing, holding, watchlistItem } from '@/lib/server/db/schema';
+import { normalizeTicker, nowIso } from '@/lib/server/utils';
 
 type HoldingRow = typeof holding.$inferSelect;
 
@@ -30,7 +31,7 @@ function sortByMarketValueDesc(rows: Holding[]) {
 
 function normalizeHoldingInput(input: { ticker: string; shares: number; avgCost: number; currentPrice: number }) {
   return {
-    ticker: input.ticker.trim().toUpperCase(),
+    ticker: normalizeTicker(input.ticker),
     shares: input.shares.toFixed(6),
     avg_cost: input.avgCost.toFixed(6),
     current_price: input.currentPrice.toFixed(6)
@@ -82,7 +83,7 @@ export async function listUserHoldings(userId: string) {
 }
 
 export async function getHoldingByTicker(userId: string, ticker: string) {
-  const normalizedTicker = ticker.trim().toUpperCase();
+  const normalizedTicker = normalizeTicker(ticker);
   if (!normalizedTicker) {
     return null;
   }
@@ -104,8 +105,8 @@ export async function upsertHoldingRecord(input: {
   currentPrice?: number;
   companyName?: string;
 }) {
-  const ticker = input.ticker.trim().toUpperCase();
-  const now = new Date().toISOString();
+  const ticker = normalizeTicker(input.ticker);
+  const now = nowIso();
 
   const [existing] = await db
     .select()
@@ -251,8 +252,8 @@ export async function updateHoldingByIdRecord(input: {
     shares: shares.toFixed(6),
     avg_cost: avgCost.toFixed(6),
     current_price: currentPrice.toFixed(6),
-    updated_at: new Date().toISOString(),
-    last_price_at: new Date().toISOString()
+    updated_at: nowIso(),
+    last_price_at: nowIso()
   });
 
   const [updated] = await db