perf+fix: audit phase 0/1 — parallel textures, dead weight, two real bugs

Findings from a full frontend audit (static read + live instrumentation of
production). This covers the "bleeding" and performance phases.

Bug fixes:
- StatsPanel branch collapse/expand never re-rendered. Two Svelte 5 defects:
  $state(new Set()) is not proxied (proxy.js bails on non-object/array
  prototypes), so .add()/.delete() were untracked; and the Svelte 4
  `x = x` reactivity idiom is a no-op in runes mode, where sources use a
  strict `equals` comparator. Switched to SvelteSet and dropped the
  self-assignment. Verified: aria-expanded now flips and rows 28<->24.
- The closed stats panel's gold box-shadow (8px offset + 80px blur) bled
  ~88px past its right edge, painting a permanent olive stripe down the
  left of the viewport on every page view. Offset the closed transform
  past the shadow.
- data.ts shipped a placeholder repoUrl (github.com/yourusername/...), a
  live 404 on the node describing this very site. Also removed the
  "Tailwind CSS" techStack claim; it is not a dependency of this project.

Performance:
- nodes.ts awaited Assets.load() inside the node loop, serialising ~56 icon
  round-trips before the tree could render or accept input. Now one
  parallel batch. Measured: all 78 tree icon requests start at ~28ms and
  complete within ~618ms.
- isLoading was cleared right after app.init(), before a single texture
  existed, so the spinner resolved onto an empty screen. Moved to after
  the scene graph is built.
- Renderer left antialias on (costly, ~no benefit on soft glow circles)
  and resolution/autoDensity at defaults (blurry on HiDPI). Now
  antialias:false, resolution:min(dpr,2), autoDensity, high-performance.
- cacheAsTexture on the fully-static gradient (16 full-screen fills) and
  vignette (13); interactiveChildren:false on background containers.
- Dust ticker allocated a fresh closure per frame via forEach; replaced
  with a named function and an indexed loop.

Dead weight:
- static/{headshot,profile}.jpg.original (8.6MB, 83% of the static payload)
  were committed and deployed verbatim by adapter-static, publicly
  fetchable and referenced by nothing. Moved to a gitignored assets-src/
  so the full-res sources stay on disk without shipping.
- precompress:true so nginx gzip_static/brotli_static have siblings to
  serve (the origin currently sends everything uncompressed).

build/ 11.13MB -> 3.7MB. JS wire 727.6KB raw -> 232KB gzip / 202.7KB brotli.
svelte-check clean, 14/14 tests pass.

Note: the matching nginx change lives in the gitignored homelab/default.conf
and must be applied to the container separately.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/lib/components/SkillTree.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { onMount } from 'svelte';
+	import { SvelteSet } from 'svelte/reactivity';
 	import { Application, Container } from 'pixi.js';
 	import type { TreeNode } from '$lib/data';
 	import { categoryColorHex } from '$lib/theme';
@@ -45,7 +46,9 @@
 
 	// Stats panel state
 	let statsPanelVisible = $state(false);
-	let expandedBranches = $state(new Set<string>(BRANCH_IDS)); // All expanded by default
+	// SvelteSet, not $state(new Set()) — Svelte 5 does not proxy a plain Set, so
+	// .add()/.delete() would be untracked and the panel would never re-render.
+	let expandedBranches = new SvelteSet<string>(BRANCH_IDS); // All expanded by default
 
 	function openModal(node: TreeNode) {
 		selectedNode = node;
@@ -81,7 +84,6 @@
 		} else {
 			expandedBranches.add(branchId);
 		}
-		expandedBranches = expandedBranches; // Trigger reactivity
 	}
 
 	// Stats calculations (reactive)
@@ -110,16 +112,18 @@
 		await app.init({
 			background: '#05050a',
 			resizeTo: container,
-			antialias: true
+			// The scene is soft glow circles — MSAA costs fill rate and buys almost
+			// nothing here. Sharpness comes from rendering at device resolution instead.
+			antialias: false,
+			resolution: Math.min(window.devicePixelRatio || 1, 2),
+			autoDensity: true,
+			powerPreference: 'high-performance'
 		});
 
 		// PixiJS owns this canvas, not Svelte — mounting it directly is intentional.
 		// eslint-disable-next-line svelte/no-dom-manipulating
 		container.appendChild(app.canvas);
 
-		// Hide loading indicator - PixiJS is ready, welcome title will be LCP
-		isLoading = false;
-
 		// Background layers (gradient → nebula → stars → dust → vignette)
 		const bg = createBackground(app, isMobile);
 
@@ -149,6 +153,11 @@
 			}
 		});
 
+		// Textures are loaded and the scene graph is built — only now is the canvas
+		// genuinely ready. (This used to fire right after app.init(), so the spinner
+		// resolved onto an empty screen.)
+		isLoading = false;
+
 		// Pan / zoom / parallax + keyboard navigation
 		const detachPanZoom = attachPanZoom(controller, {
 			onTooltipMove: (x, y) => {