Fix network map mobile overflow and infer MQTT hops from SNR=0 (#2)

* Fix network map mobile overflow and infer MQTT hops from SNR=0

- Add min-h-0 and flex-shrink-0 to map layout so legend/actions don't
  overflow the viewport on mobile
- Infer viaMqtt=true for traceroute hops with SNR exactly 0
- Change MQTT hop color from purple to orange across map, legend, and
  node detail badges

https://claude.ai/code/session_01Ffqq7YPCJE28uUFR88eK7C

* Revert MQTT color to purple; keep SNR=0 MQTT inference

The color change was unintended — MQTT hops should stay purple. The
SNR=0 inference in traceroute processing correctly marks those hops
as viaMqtt so they render as purple dashed lines.

https://claude.ai/code/session_01Ffqq7YPCJE28uUFR88eK7C

* Fix test setup: mock URL.createObjectURL for maplibre-gl

maplibre-gl calls URL.createObjectURL during import for its worker
setup, which doesn't exist in jsdom. Add the mock to test setup.

https://claude.ai/code/session_01Ffqq7YPCJE28uUFR88eK7C

* Run go fmt on unformatted files

https://claude.ai/code/session_01Ffqq7YPCJE28uUFR88eK7C

---------

Co-authored-by: Claude <noreply@anthropic.com>

web/src/routes/map.tsx

@@ -26,7 +26,7 @@ function MapPage() {
   return (
     <PageWrapper>
       <div className="flex flex-col h-[calc(100vh-7rem)] md:h-[calc(100vh-5rem)]">
-        <div className="flex-1 flex flex-col">
+        <div className="flex-1 flex flex-col min-h-0">
           <NetworkMap
             fullHeight
             ref={mapRef as any}
@@ -34,7 +34,7 @@ function MapPage() {
             showLinks={showLinks}
           />
 
-          <div className="mt-2 rounded-lg p-2 text-xs flex items-center justify-between effect-inset">
+          <div className="mt-2 rounded-lg p-2 text-xs flex items-center justify-between effect-inset flex-shrink-0">
             <div className="flex flex-wrap gap-2">
               <div className="flex items-center gap-x-3 gap-y-1 flex-wrap">
                 <span className={`inline-flex items-center px-2 py-0.5 rounded ${getNodeColors(ActivityLevel.RECENT, false).textClass} ${getNodeColors(ActivityLevel.RECENT, false).background}`}>

web/src/store/slices/topologySlice.ts

@@ -156,6 +156,8 @@ function processTopology(
     for (let i = 0; i < forwardPath.length - 1; i++) {
       const cap = Math.min(snrTowards.length, forwardPath.length - 1);
       const snr = i < cap ? snrTowards[i] / 4 : undefined;
+      // SNR of exactly 0 indicates an MQTT-bridged hop
+      const hopViaMqtt = snr === 0 || !!data.viaMqtt;
       upsertObservation(
         state,
         forwardPath[i],     // sender
@@ -163,7 +165,7 @@ function processTopology(
         snr,
         undefined,
         "traceroute",
-        !!data.viaMqtt,
+        hopViaMqtt,
         timestamp,
         hopCount
       );
@@ -176,6 +178,8 @@ function processTopology(
     for (let i = 0; i < returnPath.length - 1; i++) {
       const cap = Math.min(snrBack.length, returnPath.length - 1);
       const snr = i < cap ? snrBack[i] / 4 : undefined;
+      // SNR of exactly 0 indicates an MQTT-bridged hop
+      const hopViaMqtt = snr === 0 || !!data.viaMqtt;
       upsertObservation(
         state,
         returnPath[i],
@@ -183,7 +187,7 @@ function processTopology(
         snr,
         undefined,
         "traceroute",
-        !!data.viaMqtt,
+        hopViaMqtt,
         timestamp,
         hopCount
       );

web/src/test/setup.ts

@@ -1,6 +1,14 @@
 import '@testing-library/jest-dom';
 import { vi } from 'vitest';
 
+// Mock URL.createObjectURL (required by maplibre-gl worker setup)
+if (typeof window.URL.createObjectURL === 'undefined') {
+  window.URL.createObjectURL = vi.fn(() => '');
+}
+if (typeof window.URL.revokeObjectURL === 'undefined') {
+  window.URL.revokeObjectURL = vi.fn();
+}
+
 // Mock for window.matchMedia
 Object.defineProperty(window, 'matchMedia', {
   writable: true,