fix(dashboard): Simplify data loader UI

Remove confusing 'Load ../debtmap.json' and 'Reload' buttons.
Users should use 'Load JSON File' to select their file.
Status now shows 'No file loaded' initially and updates with
the loaded filename.

Author: iepathos

viz-dev/dashboard.html

@@ -321,9 +321,7 @@ <h1>Debtmap Dashboard</h1>
     <div class="data-loader">
         <button onclick="document.getElementById('file-input').click()">Load JSON File</button>
         <input type="file" id="file-input" accept=".json" onchange="loadFromFile(event)">
-        <button class="secondary" onclick="loadDefaultJson()">Load ../debtmap.json</button>
-        <button class="secondary" onclick="reloadData()">Reload</button>
-        <span class="status" id="load-status">No data loaded</span>
+        <span class="status" id="load-status">No file loaded</span>
     </div>
 
     <!-- Summary Cards (shown after data load) -->
@@ -489,25 +487,6 @@ <h3>No Data Loaded</h3>
             reader.readAsText(file);
         }
 
-        async function loadDefaultJson() {
-            updateStatus('Loading...', '');
-            try {
-                // Add cache-busting parameter to force fresh fetch
-                const response = await fetch(`../debtmap.json?t=${Date.now()}`);
-                if (!response.ok) throw new Error(`HTTP ${response.status}`);
-                rawData = await response.json();
-                processAndRender();
-                updateStatus('Loaded: debtmap.json', 'loaded');
-            } catch (err) {
-                updateStatus(`Error: ${err.message}. Try using a local server.`, 'error');
-            }
-        }
-
-        function reloadData() {
-            // Re-fetch the JSON file instead of just re-rendering cached data
-            loadDefaultJson();
-        }
-
         function updateStatus(msg, className) {
             const status = document.getElementById('load-status');
             status.textContent = msg;