feat(ui): frontend polish sweep — 8 UX fixes

- DeckyFleet: card click opens inspect side-drawer instead of
  auto-filtering (localSearch filter behavior removed)
- Dashboard: LIVE FEED / DECKIES UNDER SIEGE / TOP ATTACKERS panels
  now have fixed max-height with overflow scroll instead of growing
- parseEventBody: defensive RFC 5424 header strip so raw syslog lines
  from the collector render as k=v pills instead of raw text
- Attackers: search placeholder updated; activity (Active/Passive/
  Inactive) and country chip filters added on top of existing IP search
- Credentials + Bounty: sortable column headers (click to asc/desc/clear)
- SwarmHosts + RemoteUpdates: icon extracted from <h1> into flex div
  with violet-accent class, matching site-wide Identities pattern
- Swarm.css: fix --panel-border undefined variable → --border so the
  title border-bottom line is visible on SwarmHosts and RemoteUpdates

decnet_web/src/components/Swarm.css

@@ -5,7 +5,7 @@
   gap: 24px;
   padding-bottom: 16px;
   margin-bottom: 24px;
-  border-bottom: 1px solid var(--panel-border);
+  border-bottom: 1px solid var(--border);
 }
 
 .swarm-root .page-title-group {