perf(web/icons): per-icon lucide imports via centralised alias

Route all lucide-react icon usage through a single src/icons.ts
re-export that imports each icon from its own per-icon module
(lucide-react/dist/esm/icons/<name>) instead of the barrel.

Bundle-size impact: none (29kB icons chunk unchanged — tree-shaking
was already effective with sideEffects:false). Dev-experience win:
Vite transforms 247 modules instead of 1848 because the dep
optimiser no longer pre-bundles the full lucide barrel — faster
cold start and HMR.

Ambient d.ts declares the wildcard module so TS accepts per-icon
imports; lucide ships .d.ts only for the barrel.

Seven icons were renamed upstream and still work through the barrel
via aliases (AlertTriangle -> triangle-alert, BarChart3 -> chart-column,
CheckCircle -> circle-check-big, Filter -> funnel, PlusCircle ->
circle-plus, Sliders -> sliders-vertical, UploadCloud -> cloud-upload,
Fingerprint -> fingerprint-pattern). Component call sites stay on
the legacy names; the renames live only in icons.ts.

decnet_web/src/components/CommandPalette/CommandPalette.tsx

@@ -3,7 +3,7 @@ import {
   LayoutDashboard, Server, Network, Terminal, Archive, Crosshair,
   PlusCircle, Pause, RefreshCw, Download, HardDrive, Package, Settings,
   SearchX, Keyboard, Webhook,
-} from 'lucide-react';
+} from '../../icons';
 import EmptyState from '../EmptyState/EmptyState';
 import './CommandPalette.css';