add a transmission sidecar and ui

officer-transmission is a new pm2 peer that owns the transmission rpc
connection and exposes a curated /_officer/* contract instead of proxying
raw rpc. it absorbs the three quirks callers otherwise have to know about:
the 409 x-transmission-session-id handshake, failures returned as
{"result": "..."} inside http 200, and basic auth where an empty username
must send no header at all.

/transmission is the ui, on the workspace/panel framework: a filter nav and
three sections (torrents, stats, settings). the torrent list is virtualised
with 30 available columns, multi-select, and a right-click menu; the detail
pane covers general, files as a real tree, peers and trackers. filters and
the open torrent live in the url, so a filtered view is a link.

phase 1 goal was parity with _references/transmission-web. follow-up work is
recorded in TODO.md.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/apps/officer-web/Screens/Dashboard/Layout/Dock.tsx

@@ -135,6 +135,7 @@ import {
   Activity,
   Radio,
   Network,
+  ArrowDownUp,
 } from 'lucide-react';
 
 export const ALL_DOCK_ITEMS: DockItem[] = [
@@ -145,6 +146,7 @@ export const ALL_DOCK_ITEMS: DockItem[] = [
   { label: 'Music', to: '/music', icon: Music, color: '#22c55e' },
   { label: 'Soulseek', to: '/soulseek', image: '/slskd.png', color: '#ffffff' },
   { label: 'Headscale', to: '/headscale', icon: Network, color: '#818cf8' },
+  { label: 'Transmission', to: '/transmission', icon: ArrowDownUp, color: '#e11d48' },
   { label: 'Editor', to: '/code-editor', icon: Code, color: '#a78bfa' },
   { label: 'Plans', to: '/plans', icon: FileText, color: '#f472b6' },
   { label: 'Jobs', to: '/jobs', icon: Workflow, color: '#14b8a6' },