Surface structured RCON failure reasons in the fleet UI

rconGetStatus previously collapsed at least five distinct failure modes
(no password, no port, socket error, timeout, bad reply) into a single
null return, so the UI could only say "rcon unreachable" — useless when
diagnosing a real Alcatraz outage.

Refactored to rconStatusResult() returning a discriminated union with a
RconFailure reason and human-facing detail. The worker persists these as
"<reason>:<detail>" in last_error (no schema change). /api/servers now
returns the derived endpoint (host:port) per server plus a top-level
integrations block (rcon/komodo configured, timeout, default host).

Server detail page gains an RCON diagnostic panel when health is not
online: shows the exact endpoint being dialed, integration status,
timeout, a color-coded reason tag, the detail, and a targeted fix hint.
Wrong-password replies are detected via "bad rcon" text in the print
body.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/lib/server/pipeline/bus.ts

@@ -1,5 +1,5 @@
 import { EventEmitter } from 'node:events';
-import type { RconPlayer } from '../integrations/rcon.js';
+import type { RconEndpoint, RconFailure, RconPlayer } from '../integrations/rcon.js';
 import type { Health } from '../fleet/health.js';
 
 // One in-process event bus, multiplexed by the SSE endpoints. Kept separate
@@ -15,6 +15,8 @@ export interface ServerStatusEntry {
     health: Health;
     lastSeenAt: string | null;
     lastError: string | null;
+    endpoint: RconEndpoint | null;
+    reason: RconFailure | null;
 }
 
 export type PipelineEvent =