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>

.gitignore

@@ -27,3 +27,8 @@ Thumbs.db
 # Vite
 vite.config.js.timestamp-*
 vite.config.ts.timestamp-*
+
+homelab/*
+# Full-res source images — kept locally, never deployed (adapter-static copies all of static/)
+assets-src/
+*.original