Add FMCSA API fallback for name search when local DB is empty

Tries local fmcsa_carriers table first (ILIKE partial match).
If no results, falls back to FMCSA QCMobile API name search.
Ensures name search works even before full 2M census is loaded.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/src/routes/dot-lookup.ts

@@ -322,6 +322,7 @@ router.get("/api/v1/dot/search", async (req, res) => {
   }
 
   try {
+    // Try local database first
     const result = await pool.query(
       `SELECT dot_number, legal_name, dba_name, phy_city, phy_state,
               nbr_power_unit, authorized_for_hire, mcs150_parsed
@@ -332,9 +333,54 @@ router.get("/api/v1/dot/search", async (req, res) => {
       [`%${name}%`],
     );
 
+    if (result.rows.length > 0) {
+      res.json({
+        results: result.rows,
+        count: result.rows.length,
+        query: name,
+        source: "FMCSA Motor Carrier Census",
+      });
+      return;
+    }
+
+    // Fallback: FMCSA QCMobile API name search
+    if (FMCSA_API_KEY) {
+      try {
+        const apiResp = await fetch(
+          `${FMCSA_BASE}/name/${encodeURIComponent(name)}?webKey=${FMCSA_API_KEY}`,
+          { signal: AbortSignal.timeout(10000), headers: { Accept: "application/json" } },
+        );
+        if (apiResp.ok) {
+          const apiData = await apiResp.json();
+          const carriers = (apiData.content || []).map((item: any) => {
+            const c = item.carrier || item;
+            return {
+              dot_number: String(c.dotNumber || ""),
+              legal_name: c.legalName || "",
+              dba_name: c.dbaName || null,
+              phy_city: c.phyCity || null,
+              phy_state: c.phyState || null,
+              nbr_power_unit: c.totalPowerUnits || null,
+              authorized_for_hire: c.allowedToOperate === "Y",
+              mcs150_parsed: null,
+            };
+          });
+          res.json({
+            results: carriers.slice(0, 50),
+            count: carriers.length,
+            query: name,
+            source: "FMCSA API (live)",
+          });
+          return;
+        }
+      } catch {
+        // API fallback failed — return empty
+      }
+    }
+
     res.json({
-      results: result.rows,
-      count: result.rows.length,
+      results: [],
+      count: 0,
       query: name,
       source: "FMCSA Motor Carrier Census",
     });