Add GPS-only backup/restore and database wipe

- Fix backup.py PRESERVED_FIELDS column names (lat/lng -> latitude/longitude)
  to match actual DB schema (pre-existing bug)
- Add backup_gps() and restore_gps() dedicated GPS-only functions
- Add /api/gps/backup and /api/gps/restore API endpoints
- Add /api/gps/restore/upload for restoring from uploaded backup files
- Add /api/db/wipe endpoint to clear all asset records
- Update UI with GPS-only Backup button, Restore GPS from File picker,
  and Wipe All Assets with double-confirmation dialog
- Fix backup listing to scan both seed-data/ and project root

web/static/index.html

@@ -575,8 +575,9 @@
     <!-- Backup Management ───────────────────────────────────────────────── -->
     <div class="card" id="cardBackup" style="margin-top:20px">
       <h2>💾 Backup Management</h2>
-      <div class="btn-row" style="margin-bottom:12px">
-        <button class="btn btn-primary btn-sm" onclick="createBackup()">💾 Create Backup</button>
+      <div class="btn-row" style="margin-bottom:8px">
+        <button class="btn btn-primary btn-sm" onclick="createBackup()">💾 Full Backup</button>
+        <button class="btn btn-sm" style="background:var(--accent2);color:#fff;border:none;cursor:pointer;border-radius:6px;padding:6px 14px;font-size:13px" onclick="createGpsBackup()">📍 GPS-Only Backup</button>
         <span id="backupStatus" style="font-size:13px;color:var(--text2)"></span>
       </div>
       <div id="backupList">
@@ -584,6 +585,20 @@
       </div>
     </div>
 
+    <!-- Database Management ────────────────────────────────────────────── -->
+    <div class="card" style="margin-top:20px;border-color:rgba(255,80,80,0.2);">
+      <h2 style="color:var(--red);">⚠️ Database Management</h2>
+      <div style="font-size:13px;color:var(--text3);margin-bottom:12px;">
+        These operations modify the underlying asset database directly.
+        Always <strong>backup GPS first</strong> to avoid losing coordinate data.
+      </div>
+      <div class="btn-row" style="gap:8px;flex-wrap:wrap;">
+        <button class="btn btn-danger btn-sm" onclick="restoreFromFile()">📍 Restore GPS from File</button>
+        <button class="btn btn-danger btn-sm" onclick="wipeDatabase()">🗑️ Wipe All Assets</button>
+        <span id="dbManageStatus" style="font-size:13px;color:var(--text2)"></span>
+      </div>
+    </div>
+
   </div>
 
   <script>
@@ -999,6 +1014,70 @@
         setTimeout(loadBackupList, 2000);
       }
     }
+
+    // ─── GPS-only Backup ──────────────────────────────────────────────
+
+    async function createGpsBackup() {
+      const statusEl = document.getElementById('backupStatus');
+      statusEl.innerHTML = '<span class="spinner"></span> Backing up GPS...';
+      try {
+        const res = await fetch('/api/gps/backup', { method: 'POST' });
+        if (!res.ok) throw new Error((await res.json()).detail || 'GPS backup failed');
+        const d = await res.json();
+        statusEl.innerHTML = `<span style="color:var(--green)">✅ GPS backup: ${esc(d.backup_path)}</span>`;
+        loadBackupList();
+        refreshDashboard();
+      } catch (e) {
+        statusEl.innerHTML = `<span style="color:var(--red)">❌ ${esc(e.message)}</span>`;
+      }
+    }
+
+    // ─── Restore GPS from File (file picker) ──────────────────────────
+
+    function restoreFromFile() {
+      // Create hidden file input for .json.gz files
+      const input = document.createElement('input');
+      input.type = 'file';
+      input.accept = '.json.gz,.json';
+      input.onchange = async (e) => {
+        const file = e.target.files[0];
+        if (!file) return;
+        const statusEl = document.getElementById('dbManageStatus');
+        statusEl.innerHTML = `<span class="spinner"></span> Uploading & restoring GPS from ${esc(file.name)}...`;
+
+        // Upload to temp location then restore
+        const form = new FormData();
+        form.append('backup_file', file);
+        try {
+          const res = await fetch('/api/gps/restore/upload', { method: 'POST', body: form });
+          if (!res.ok) throw new Error((await res.json()).detail || 'Restore failed');
+          const d = await res.json();
+          statusEl.innerHTML = `<span style="color:var(--green)">✅ GPS restored from: ${esc(d.restored_from)}</span>`;
+          refreshDashboard();
+        } catch (e) {
+          statusEl.innerHTML = `<span style="color:var(--red)">❌ ${esc(e.message)}</span>`;
+        }
+      };
+      input.click();
+    }
+
+    // ─── Wipe Database ────────────────────────────────────────────────
+
+    async function wipeDatabase() {
+      if (!confirm('⚠️ This will DELETE ALL ASSET RECORDS from the database. This cannot be undone without a backup.\n\nHave you backed up GPS coordinates first?')) return;
+      if (!confirm('Final confirmation: Are you sure you want to delete ALL assets?')) return;
+      const statusEl = document.getElementById('dbManageStatus');
+      statusEl.innerHTML = '<span class="spinner"></span> Wiping database...';
+      try {
+        const res = await fetch('/api/db/wipe', { method: 'POST' });
+        if (!res.ok) throw new Error((await res.json()).detail || 'Wipe failed');
+        const d = await res.json();
+        statusEl.innerHTML = `<span style="color:var(--red)">🗑️ Deleted ${d.records_deleted} records. Database is now empty.</span>`;
+        refreshDashboard();
+      } catch (e) {
+        statusEl.innerHTML = `<span style="color:var(--red)">❌ ${esc(e.message)}</span>`;
+      }
+    }
   </script>
 </body>
 </html>