Initial commit: timeline-elements-ui library

Angular 19 component library for timelines and event tracking:
timeline, Gantt chart, event cards, date markers, connectors,
and custom event templates. Includes signal-based services,
SCSS design tokens with dark mode, and TypeScript type definitions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/tl-timeline-toolbar/tl-timeline-toolbar.component.scss

@@ -0,0 +1,22 @@
+.tl-timeline-toolbar {
+  display: flex;
+  align-items: center;
+  gap: var(--spacing-xs, 0.5rem);
+  padding: var(--spacing-xs, 0.5rem) var(--spacing-md, 1rem);
+  background: var(--color-bg-secondary, #f9fafb);
+  border: 1px solid var(--color-border-primary, #e5e7eb);
+  border-radius: var(--radius-lg, 0.5rem);
+  margin-bottom: var(--spacing-sm, 0.75rem);
+
+  &__search {
+    flex: 1;
+    min-width: 200px;
+  }
+
+  &__actions {
+    display: flex;
+    gap: var(--spacing-xs, 0.5rem);
+    align-items: center;
+    margin-left: auto;
+  }
+}