fix: performance hardening — eliminate full table scans (#9)

Inventory:
- /issues: replaced full scan + client filter with NocoDB server-side
  WHERE filter (Received eq Issues/Issue). Single query, ~200 rows max.
- /needs-review-count: replaced full scan with server-side WHERE +
  limit=1 + pageInfo.totalRows. Returns count without fetching data.

Budget:
- buildLookups(): added 2-minute cache for payee/account/category maps.
  Eliminates 3 API calls per request for repeated queries.
- /summary cache (added earlier): 1-minute TTL still active.

Files: services/inventory/server.js, services/budget/server.js

services/budget/server.js

@@ -102,8 +102,12 @@ function currentMonth() {
   return `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}`;
 }
 
-/** Build lookup maps for payees, accounts, and categories. */
+/** Build lookup maps for payees, accounts, and categories (cached 2 min). */
+let _lookupsCache = { data: null, expiresAt: 0 };
 async function buildLookups() {
+  if (_lookupsCache.data && Date.now() < _lookupsCache.expiresAt) {
+    return _lookupsCache.data;
+  }
   const [payees, accounts, categories] = await Promise.all([
     api.getPayees(),
     api.getAccounts(),
@@ -115,7 +119,9 @@ async function buildLookups() {
   for (const a of accounts) accountMap[a.id] = a.name;
   const categoryMap = {};
   for (const c of categories) categoryMap[c.id] = c.name;
-  return { payeeMap, accountMap, categoryMap };
+  const result = { payeeMap, accountMap, categoryMap };
+  _lookupsCache = { data: result, expiresAt: Date.now() + 120000 };
+  return result;
 }
 
 /** Enrich a transaction with resolved names. */

services/inventory/server.js

@@ -362,30 +362,24 @@ app.get('/summary', async (req, res) => {
     }
 });
 
-// Get items with issues (full details)
+// Get items with issues (full details) — server-side filtered
 app.get('/issues', async (req, res) => {
     try {
         if (!config.apiToken) {
             return res.status(500).json({ error: 'NocoDB API token not configured' });
         }
-        let allRows = [];
-        let offset = 0;
-        const limit = 1000;
-        let hasMore = true;
-        while (hasMore && offset < 10000) {
         const response = await axios.get(
             config.ncodbUrl + '/api/v1/db/data/noco/' + config.baseId + '/' + config.tableId,
-                { headers: { 'xc-token': config.apiToken, 'Accept': 'application/json' }, params: { limit, offset } }
-            );
-            const pageRows = response.data.list || [];
-            allRows = allRows.concat(pageRows);
-            hasMore = pageRows.length === limit;
-            offset += limit;
+            {
+                headers: { 'xc-token': config.apiToken, 'Accept': 'application/json' },
+                params: {
+                    where: '(Received,eq,Issues)~or(Received,eq,Issue)',
+                    limit: 200,
+                    sort: '-Id'
                 }
-        const issues = allRows.filter(row => {
-            const val = (row.Received || row.received || '').toLowerCase();
-            return val === 'issues' || val === 'issue';
-        }).map(row => ({
+            }
+        );
+        const issues = (response.data.list || []).map(row => ({
             id: row.Id,
             item: row.Item || row.Name || 'Unknown',
             orderNumber: row['Order Number'] || '',
@@ -403,50 +397,25 @@ app.get('/issues', async (req, res) => {
 });
 
 // Get count of rows that have issues
+// Count of items with issues — server-side filtered, single query
 app.get('/needs-review-count', async (req, res) => {
     try {
         if (!config.apiToken) {
             return res.status(500).json({ error: 'NocoDB API token not configured' });
         }
-        
-        console.log('Fetching issues count...');
-        
-        // Fetch all records with pagination
-        let allRows = [];
-        let offset = 0;
-        const limit = 1000;
-        let hasMore = true;
-        
-        while (hasMore && offset < 10000) {
         const response = await axios.get(
             config.ncodbUrl + '/api/v1/db/data/noco/' + config.baseId + '/' + config.tableId,
             {
-                    headers: {
-                        'xc-token': config.apiToken,
-                        'Accept': 'application/json'
-                    },
+                headers: { 'xc-token': config.apiToken, 'Accept': 'application/json' },
                 params: {
-                        limit: limit,
-                        offset: offset
+                    where: '(Received,eq,Issues)~or(Received,eq,Issue)~or(Received,eq,Needs Review)',
+                    limit: 1,
+                    fields: 'Id'
                 }
             }
         );
-            
-            const pageRows = response.data.list || [];
-            allRows = allRows.concat(pageRows);
-            hasMore = pageRows.length === limit;
-            offset += limit;
-        }
-        
-        console.log('API response received, total rows:', allRows.length);
-        const issuesCount = allRows.filter(row => {
-            const receivedValue = row.Received || row.received;
-            return receivedValue === 'Issues' || receivedValue === 'Issue';
-        }).length;
-        
-        console.log('Found ' + issuesCount + ' items with issues');
-        res.json({ count: issuesCount });
-        
+        const count = response.data.pageInfo?.totalRows || (response.data.list || []).length;
+        res.json({ count });
     } catch (error) {
         console.error('Error fetching issues count:', error.message);
         res.status(500).json({ error: 'Failed to fetch count', details: error.message });