Add comprehensive Obsidian image rendering with multi-strategy resolution, attachment indexing, and API endpoints for image serving with MIME type detection and rescan functionality

frontend/style.css

@@ -1191,6 +1191,38 @@ select {
   cursor: default;
 }
 
+/* Image placeholders */
+.image-not-found {
+  display: inline-block;
+  padding: 8px 12px;
+  background: var(--danger-bg);
+  color: var(--danger);
+  border: 1px dashed var(--danger);
+  border-radius: 4px;
+  font-family: 'JetBrains Mono', monospace;
+  font-size: 0.85rem;
+  cursor: help;
+}
+
+/* Markdown images */
+.file-content img {
+  max-width: 100%;
+  height: auto;
+  display: block;
+  margin: 16px 0;
+  border-radius: 6px;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
+}
+
+.file-content a img {
+  cursor: pointer;
+  transition: opacity 0.2s ease;
+}
+
+.file-content a img:hover {
+  opacity: 0.85;
+}
+
 /* --- Search Results --- */
 .search-results {
   padding: 0;