Improve live node positions and expose precision metadata (#231)

* Fetch latest node positions and precision metadata

* Stop showing position source and precision in UI

* Guard node positions against stale merges

web/views/index.erb

@@ -1813,12 +1813,88 @@ var(--fg); }
       return r.json();
     }
 
+    async function fetchPositions(limit = NODE_LIMIT) {
+      const r = await fetch(`/api/positions?limit=${limit}`, { cache: 'no-store' });
+      if (!r.ok) throw new Error('HTTP ' + r.status);
+      return r.json();
+    }
+
     function toFiniteNumber(value) {
       if (value == null || value === '') return null;
       const num = typeof value === 'number' ? value : Number(value);
       return Number.isFinite(num) ? num : null;
     }
 
+    function resolveTimestampSeconds(numeric, isoString) {
+      const parsedNumeric = toFiniteNumber(numeric);
+      if (parsedNumeric != null) return parsedNumeric;
+      if (typeof isoString === 'string' && isoString.length) {
+        const parsedIso = Date.parse(isoString);
+        if (Number.isFinite(parsedIso)) {
+          return parsedIso / 1000;
+        }
+      }
+      return null;
+    }
+
+    function mergePositionsIntoNodes(nodes, positions) {
+      if (!Array.isArray(nodes) || !Array.isArray(positions) || nodes.length === 0) return;
+
+      const nodesById = new Map();
+      for (const node of nodes) {
+        if (!node || typeof node !== 'object') continue;
+        const key = typeof node.node_id === 'string' ? node.node_id : null;
+        if (key) nodesById.set(key, node);
+      }
+
+      if (nodesById.size === 0) return;
+
+      const updated = new Set();
+      for (const pos of positions) {
+        if (!pos || typeof pos !== 'object') continue;
+        const nodeId = typeof pos.node_id === 'string' ? pos.node_id : null;
+        if (!nodeId || updated.has(nodeId)) continue;
+        const node = nodesById.get(nodeId);
+        if (!node) continue;
+
+        const lat = toFiniteNumber(pos.latitude);
+        const lon = toFiniteNumber(pos.longitude);
+        if (lat == null || lon == null) continue;
+
+        const currentTimestamp = resolveTimestampSeconds(node.position_time, node.pos_time_iso);
+        const incomingTimestamp = resolveTimestampSeconds(pos.position_time, pos.position_time_iso);
+        if (currentTimestamp != null) {
+          if (incomingTimestamp == null || incomingTimestamp <= currentTimestamp) {
+            continue;
+          }
+        }
+
+        updated.add(nodeId);
+        node.latitude = lat;
+        node.longitude = lon;
+
+        const alt = toFiniteNumber(pos.altitude);
+        if (alt != null) node.altitude = alt;
+
+        const posTime = toFiniteNumber(pos.position_time);
+        if (posTime != null) {
+          node.position_time = posTime;
+          node.pos_time_iso = typeof pos.position_time_iso === 'string' && pos.position_time_iso.length
+            ? pos.position_time_iso
+            : new Date(posTime * 1000).toISOString();
+        } else if (typeof pos.position_time_iso === 'string' && pos.position_time_iso.length) {
+          node.pos_time_iso = pos.position_time_iso;
+        }
+
+        if (pos.location_source != null && pos.location_source !== '') {
+          node.location_source = pos.location_source;
+        }
+
+        const precision = toFiniteNumber(pos.precision_bits);
+        if (precision != null) node.precision_bits = precision;
+      }
+    }
+
     function buildTelemetryIndex(entries) {
       const byNodeId = new Map();
       const byNodeNum = new Map();
@@ -1938,6 +2014,8 @@ var(--fg); }
       const frag = document.createDocumentFragment();
       for (const n of nodes) {
         const tr = document.createElement('tr');
+        const lastPositionTime = toFiniteNumber(n.position_time ?? n.positionTime);
+        const lastPositionCell = lastPositionTime != null ? timeAgo(lastPositionTime, nowSec) : '';
         tr.innerHTML = `
           <td class="mono">${n.node_id || ""}</td>
           <td>${renderShortHtml(n.short_name, n.role, n.long_name, n)}</td>
@@ -1956,7 +2034,7 @@ var(--fg); }
           <td>${fmtCoords(n.latitude)}</td>
           <td>${fmtCoords(n.longitude)}</td>
           <td>${fmtAlt(n.altitude, "m")}</td>
-          <td class="mono">${n.pos_time_iso ? `${timeAgo(n.position_time, nowSec)}` : ""}</td>`;
+          <td class="mono">${lastPositionCell}</td>`;
         frag.appendChild(tr);
       }
       tb.replaceChildren(frag);
@@ -2112,8 +2190,9 @@ var(--fg); }
         if (n.last_heard) {
           lines.push(`Last seen: ${timeAgo(n.last_heard, nowSec)}`);
         }
-        if (n.pos_time_iso) {
-          lines.push(`Last Position: ${timeAgo(n.position_time, nowSec)}`);
+        const lastPositionTime = toFiniteNumber(n.position_time ?? n.positionTime);
+        if (lastPositionTime != null) {
+          lines.push(`Last Position: ${timeAgo(lastPositionTime, nowSec)}`);
         }
         if (n.uptime_seconds) {
           lines.push(`Uptime: ${timeHum(n.uptime_seconds)}`);
@@ -2208,13 +2287,19 @@ var(--fg); }
           console.warn('telemetry refresh failed; continuing without telemetry', err);
           return [];
         });
-        const [nodes, neighborTuples, messages, telemetryEntries] = await Promise.all([
+        const positionsPromise = fetchPositions().catch(err => {
+          console.warn('position refresh failed; continuing without updates', err);
+          return [];
+        });
+        const [nodes, positions, neighborTuples, messages, telemetryEntries] = await Promise.all([
           fetchNodes(),
+          positionsPromise,
           neighborPromise,
           fetchMessages(),
           telemetryPromise,
         ]);
         nodes.forEach(applyNodeNameFallback);
+        mergePositionsIntoNodes(nodes, positions);
         computeDistances(nodes);
         mergeTelemetryIntoNodes(nodes, telemetryEntries);
         if (Array.isArray(messages)) {