chore(export-viewer): rebuild the embedded bundle, and fix the lint ignores

The offline keepsake viewer had the same two filter defects as the app: typed
suggestions were capped so a matching tag could be unselectable, and the dropdown used
`onmousedown` with a backdrop that swallowed the selection. Rebuilt into
`backend/static/export-viewer/index.html`, which `include_dir!` embeds in the binary.

The eslint ignores were unanchored, so once the export-viewer's dependencies were
installed its nested `.svelte-kit` output was linted as source. Anchored with `**/`.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/eslint.config.js

@@ -58,10 +58,16 @@ export default ts.config(
 	},
 	{
 		ignores: [
-			'.svelte-kit/',
-			'build/',
-			'dist/',
-			'node_modules/',
+			// `**/` matters: these patterns are relative to this config's directory, so a bare
+			// `.svelte-kit/` matched only the top-level one and left `export-viewer/.svelte-kit/`
+			// — SvelteKit's GENERATED types, gitignored but present after a viewer build — being
+			// linted, for 10 errors in code nobody wrote. Rebuilding the viewer is a required
+			// step whenever its source changes (it is embedded in the binary via include_dir!),
+			// so that directory exists in any normal working tree.
+			'**/.svelte-kit/',
+			'**/build/',
+			'**/dist/',
+			'**/node_modules/',
 			'static/export-viewer/',
 			'*.config.js',
 			'*.config.ts'