fix: backup storage relative to vault parent + global capture click handler for close button

- _backup_file: resolve relative backup path against vault parent (survives CWD changes)
- _get_backup_root: same resolution logic for listing
- backups.js: global document-level capture-phase click handler for .backup-close-btn
  (works regardless of innerHTML replacements, text node targets, or event bubbling)

frontend/js/backups.js

@@ -84,6 +84,16 @@ export async function openBackupViewer(vault, path) {
 // DOM helpers
 // ---------------------------------------------------------------------------
 
+// Global click handler: catches close button clicks anywhere in the document
+document.addEventListener('click', function(e) {
+  const btn = e.target.closest ? e.target.closest('.backup-close-btn') : null;
+  if (btn && state.overlay) {
+    e.stopPropagation();
+    e.preventDefault();
+    close();
+  }
+}, true);  // capture phase — fires before other handlers
+
 function createOverlay() {
   const overlay = document.createElement('div');
   overlay.className = 'obsigate-modal-overlay backup-viewer-overlay';
@@ -91,6 +101,11 @@ function createOverlay() {
     if (e.target === overlay) close();
   });
 
+  const panel = document.createElement('div');
+  panel.className = 'backup-viewer-panel';
+  panel.id = 'backup-viewer-panel';
+  overlay.appendChild(panel);
+
   // Keyboard: Escape closes the viewer
   _escHandler = (e) => {
     if (e.key === 'Escape' && state.overlay) {
@@ -99,37 +114,12 @@ function createOverlay() {
   };
   document.addEventListener('keydown', _escHandler);
 
-  const panel = document.createElement('div');
-  panel.className = 'backup-viewer-panel';
-  panel.id = 'backup-viewer-panel';
-  overlay.appendChild(panel);
-
-  // Event delegation fallback for close button (in case inline onclick fails)
-  panel.addEventListener('click', (e) => {
-    // e.target might be a text node (e.g. "×") — use parentElement as fallback
-    const target = e.target.nodeType === Node.TEXT_NODE ? e.target.parentElement : e.target;
-    const closeBtn = target && target.closest ? target.closest('.backup-close-btn') : null;
-    if (closeBtn) {
-      e.stopPropagation();
-      close();
-    }
-  });
-
   return overlay;
 }
 
 function setBody(html) {
   const panel = document.getElementById('backup-viewer-panel');
-  if (!panel) return;
-  panel.innerHTML = html;
-  // Re-bind close button after innerHTML replacement
-  const closeBtn = panel.querySelector('.backup-close-btn');
-  if (closeBtn) {
-    closeBtn.addEventListener('click', (e) => {
-      e.stopPropagation();
-      close();
-    });
-  }
+  if (panel) panel.innerHTML = html;
 }
 
 let _escHandler = null;