Add per-capsule stats detail page with live CPU/RAM charts

- New detail page at /dashboard/capsules/[id] with Stats and Files tabs
- Stats tab shows capsule info card (status, template, CPU, memory, disk,
  started, idle timeout) and two stacked Chart.js charts with live values
- Metrics API client with 10s polling and moving-average smoothing
- Capsule ID in list table is now a clickable link to the detail page
- Layout breadcrumb header (Capsules > sb-xxx) with back navigation
- Fix metrics sampler: use v.PID() directly as Firecracker PID since
  unshare -m execs (not forks) through the bash/ip-netns-exec/firecracker
  chain, so all share the same PID. Removes unused findChildPID.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/routes/dashboard/capsules/+page.svelte

@@ -443,9 +443,9 @@
 						{/if}
 						{#if searchQuery && capsule.id.toLowerCase().includes(searchQuery.toLowerCase())}
 							{@const matchIdx = capsule.id.toLowerCase().indexOf(searchQuery.toLowerCase())}
-							<span class="font-mono text-ui text-[var(--color-text-bright)]">{capsule.id.slice(0, matchIdx)}<mark class="rounded-[2px] bg-[var(--color-accent-glow-mid)] px-0.5 text-[var(--color-accent-bright)] not-italic">{capsule.id.slice(matchIdx, matchIdx + searchQuery.length)}</mark>{capsule.id.slice(matchIdx + searchQuery.length)}</span>
+							<a href="/dashboard/capsules/{capsule.id}" class="font-mono text-ui text-[var(--color-text-bright)] hover:text-[var(--color-accent-bright)] transition-colors duration-150">{capsule.id.slice(0, matchIdx)}<mark class="rounded-[2px] bg-[var(--color-accent-glow-mid)] px-0.5 text-[var(--color-accent-bright)] not-italic">{capsule.id.slice(matchIdx, matchIdx + searchQuery.length)}</mark>{capsule.id.slice(matchIdx + searchQuery.length)}</a>
 						{:else}
-							<span class="font-mono text-ui text-[var(--color-text-bright)]">{capsule.id}</span>
+							<a href="/dashboard/capsules/{capsule.id}" class="font-mono text-ui text-[var(--color-text-bright)] hover:text-[var(--color-accent-bright)] transition-colors duration-150">{capsule.id}</a>
 						{/if}
 					</div>