feat: broadcast notification target + UX improvements

Add broadcast target type that fans out notifications to multiple
child targets. Dispatch expands broadcast into children in
load_link_data() — dispatcher stays unaware. Children can be
toggled on/off via disabled_child_ids in config.

Also: dashboard provider card smaller font for names, scroll-to-form
on target edit, broadcast nav tab with counter, flag_modified fix
for JSON column updates, CLAUDE.md nav tree docs.

frontend/src/routes/+page.svelte

@@ -250,7 +250,7 @@
 						</div>
 						<div>
 							<p class="text-sm" style="color: var(--color-muted-foreground);">{card.literalLabel || t(card.label)}</p>
-							<p class="stat-value font-mono" style="animation-delay: {i * 80 + 200}ms;">
+							<p class="{card.literalValue ? 'stat-value-text' : 'stat-value'} font-mono" style="animation-delay: {i * 80 + 200}ms;">
 								{#if card.literalValue}{card.literalValue}{:else}{card.value}{/if}{#if card.suffix}<span class="stat-suffix">{card.suffix}</span>{/if}
 							</p>
 						</div>
@@ -362,6 +362,7 @@
 	.stat-card-inner { background: var(--color-card); border-radius: calc(0.75rem - 1px); padding: 1.25rem; }
 	.stat-icon { display: flex; align-items: center; justify-content: center; width: 2.75rem; height: 2.75rem; border-radius: 0.75rem; flex-shrink: 0; }
 	.stat-value { font-size: 1.75rem; font-weight: 600; line-height: 1.2; animation: countUp 0.5s ease-out both; }
+	.stat-value-text { font-size: 1rem; font-weight: 600; line-height: 1.3; animation: countUp 0.5s ease-out both; }
 	.stat-suffix { font-size: 1rem; font-weight: 400; color: var(--color-muted-foreground); }
 	.event-timeline { display: flex; flex-direction: column; }
 	.event-item { display: flex; align-items: flex-start; gap: 1rem; position: relative; padding-bottom: 0.75rem; }