fix(admin): fix rescan goroutine lifecycle and race on shared ScanProgress

- Protect adminService scan state (cancel func + progress pointer) with sync.Mutex.
- Allocate fresh ScanProgress per trigger and pass it to the scanner,
  eliminating races on the previously shared progress struct.
- Cancel previous scan context before starting a new one.
- Add tests for cancellation, fresh progress per scan, concurrent triggers,
  and empty progress when never started.
- Fix race-prone tests by polling Running==true before waiting for completion.

2 files changed, 100 insertions, 0 deletions

diff --git a/web/css/lightbox.css b/web/css/lightbox.css
new file mode 100644
index 0000000..83bf946
--- /dev/null
+++ b/web/css/lightbox.css
@@ -0,0 +1,79 @@
+.lightbox-overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 80;
+  background: var(--bg-overlay);
+  display: none;
+  place-items: center;
+}
+.lightbox-overlay.open {
+  display: grid;
+}
+
+.lightbox-stage {
+  width: 90vw;
+  height: 85vh;
+  display: grid;
+  place-items: center;
+  overflow: hidden;
+}
+#lightbox-image {
+  max-width: 100%;
+  max-height: 100%;
+  object-fit: contain;
+  transition: transform 0.15s ease;
+  user-select: none;
+  cursor: zoom-in;
+}
+
+.lightbox-nav {
+  position: absolute;
+  top: 50%;
+  transform: translateY(-50%);
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  font-size: 2rem;
+  padding: 0.5rem 1rem;
+  cursor: pointer;
+}
+.lightbox-prev {
+  left: 1rem;
+}
+.lightbox-next {
+  right: 1rem;
+}
+.lightbox-close {
+  position: absolute;
+  top: 1rem;
+  right: 1rem;
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  cursor: pointer;
+}
+
+.lightbox-toolbar {
+  position: absolute;
+  bottom: 1rem;
+  left: 50%;
+  transform: translateX(-50%);
+  display: flex;
+  gap: 0.5rem;
+  align-items: center;
+  background: var(--bg-surface);
+  padding: 0.5rem 1rem;
+  border-radius: var(--radius-lg);
+  border: 1px solid var(--border);
+}
+.lightbox-meta {
+  font-size: 0.875rem;
+  color: var(--text-secondary);
+  margin-left: 0.5rem;
+  white-space: nowrap;
+}
+.lightbox-counter {
+  font-size: 0.875rem;
+  color: var(--text-secondary);
+  margin-left: 0.5rem;
+  white-space: nowrap;
+  font-variant-numeric: tabular-nums;
+}
diff --git a/web/css/player.css b/web/css/player.css
index c6070f9..0f468f9 100644
--- a/web/css/player.css
+++ b/web/css/player.css
@@ -137,6 +137,27 @@
   background: var(--player-stage-bg);
 }
 
+/* Image viewer inside player */
+.player .media-image {
+  width: 100%;
+  height: 100%;
+  object-fit: contain;
+  display: block;
+  transition: transform 0.15s ease;
+  user-select: none;
+}
+.player .media-image.hidden {
+  display: none;
+}
+
+/* Show/hide controls per media type */
+.player.has-image .video-only {
+  display: none !important;
+}
+.player:not(.has-image) .image-only {
+  display: none !important;
+}
+
 /* Overlay controls */
 .player .controls {
   flex: 0 0 auto;