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.

1 files changed, 2 insertions, 0 deletions

diff --git a/web/sw.js b/web/sw.js
index 68bb0a1..a32b8cc 100644
--- a/web/sw.js
+++ b/web/sw.js
@@ -8,6 +8,7 @@ const ASSETS = [
   '/css/layout.css',
   '/css/components.css',
   '/css/player.css',
+  '/css/lightbox.css',
   '/css/login.css',
   '/js/app.js',
   '/js/state.js',
@@ -21,6 +22,7 @@ const ASSETS = [
   '/js/notes.js',
   '/js/admin.js',
   '/js/pwa.js',
+  '/js/lightbox.js',
   '/manifest.json',
 ];