feat: add fullscreen download action

src/client/app.ts

@@ -75,6 +75,7 @@ const overlayLoadingText = mustGet("overlay-loading-text");
 const overlayMedia = mustGet("overlay-media");
 const overlayPrev = mustGet("overlay-prev");
 const overlayNext = mustGet("overlay-next");
+const overlayDownload = mustGet("overlay-download");
 const closeOverlay = mustGet("close-overlay");
 const routeToggle = mustGet("route-toggle");
 const routeToggleIcon = mustGet("route-toggle-icon");
@@ -274,6 +275,20 @@ function syncPhotoNameInLocation(photoName) {
   }
 }
 
+function syncOverlayDownload(photo) {
+  if (!photo) {
+    overlayDownload.setAttribute("href", "#");
+    overlayDownload.setAttribute("aria-disabled", "true");
+    overlayDownload.removeAttribute("download");
+    return;
+  }
+
+  overlayDownload.href = photo.fullUrl;
+  overlayDownload.download = photo.name;
+  overlayDownload.setAttribute("aria-label", "Download photo");
+  overlayDownload.setAttribute("aria-disabled", "false");
+}
+
 function getOverlayPhotos() {
   if (!state.visiblePhotos.length) {
     return state.photos;
@@ -566,6 +581,7 @@ function openOverlay(photo) {
   overlay.setAttribute("aria-hidden", "false");
   overlayTitle.textContent = photo.name;
   overlayImage.alt = photo.name;
+  syncOverlayDownload(photo);
   overlay.classList.add("loading");
   overlayLoading.classList.add("active");
   overlayLoading.classList.remove("error");
@@ -600,6 +616,7 @@ function closeOverlayView() {
   overlayLoading.classList.remove("error");
   overlayLoadingText.textContent = "Loading full-size image...";
   overlayImage.removeAttribute("src");
+  syncOverlayDownload(null);
   syncPhotoNameInLocation("");
   overlaySwipeState = null;
 }

src/server/app-assets.ts

@@ -105,7 +105,7 @@ export const APP_STYLES = `      :root {
         --overlay-media-bg: rgba(248, 250, 252, 0.94);
         --overlay-media-border: rgba(148, 163, 184, 0.26);
         --overlay-media-shadow: 0 10px 24px rgba(15, 23, 42, 0.08);
-        --overlay-caption-text: rgba(248, 250, 252, 0.95);
+        --overlay-caption-text: #303030;
         --card-border: rgba(15, 23, 42, 0.11);
         --timeline-surface: rgba(255, 255, 255, 0.84);
         --timeline-surface-soft: rgba(255, 255, 255, 0.94);
@@ -730,6 +730,38 @@ export const APP_STYLES = `      :root {
         border-color: var(--timeline-border-strong);
       }
 
+      .overlay-download {
+        position: fixed;
+        top: 16px;
+        right: 64px;
+        z-index: 1001;
+        width: 40px;
+        height: 40px;
+        padding: 0;
+        justify-content: center;
+        background: var(--timeline-surface-soft);
+        color: var(--timeline-text);
+        border: 1px solid var(--timeline-border);
+        box-shadow: var(--shadow-soft);
+        backdrop-filter: blur(14px);
+        text-decoration: none;
+      }
+
+      .overlay-action {
+        display: inline-flex;
+        align-items: center;
+      }
+
+      .overlay-download:hover {
+        background: var(--timeline-surface-strong);
+        border-color: var(--timeline-border-strong);
+      }
+
+      .overlay-download[aria-disabled="true"] {
+        opacity: 0.45;
+        pointer-events: none;
+      }
+
       .overlay-nav {
         position: fixed;
         top: 50%;

src/server/page-template.ts

@@ -147,9 +147,16 @@ ${APP_STYLES}
           </svg>
         </span>
       </button>
-      <button class="close overlay-close" id="close-overlay" type="button" aria-label="Close photo">
-        x
-      </button>
+      <a class="overlay-action overlay-download" id="overlay-download" href="#" download aria-label="Download photo">
+        <span class="button-icon" aria-hidden="true">
+          <svg viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+            <path d="M8 2v7" stroke="currentColor" stroke-width="1.6" stroke-linecap="round"/>
+            <path d="M5 6.5 8 9.5 11 6.5" stroke="currentColor" stroke-width="1.6" stroke-linecap="round" stroke-linejoin="round"/>
+            <path d="M3 12.5h10" stroke="currentColor" stroke-width="1.6" stroke-linecap="round"/>
+          </svg>
+        </span>
+      </a>
+      <button class="close overlay-close" id="close-overlay" type="button" aria-label="Close photo">x</button>
       <div class="overlay-card" id="overlay-card">
         <div class="overlay-media" id="overlay-media">
           <div class="overlay-loading" id="overlay-loading" aria-live="polite" aria-atomic="true">