refactor: centralize theme/config/utils + fix data and console bugs

Phase 1 of the cohesion refactor (behavior-preserving):

Single source of truth:
- New src/lib/theme.ts: category colors (moved from data.ts, re-exported
  for back-compat), derived hex strings, nebula palette, UI colors, CSS var map
- New src/lib/config.ts: breakpoint, zoom, parallax, node radii, particle
  counts, animation timings (previously scattered magic numbers)
- New src/lib/utils/tree.ts: getNodeById, getNodeRadius, getDistanceFromOrigin,
  getBeamIntensity (pure helpers lifted out of onMount)
- New src/lib/utils/stats.ts: branch ids/labels, proficiency order, and the
  stats-panel aggregation helpers (deduped from inline copies)
- SkillTree.svelte now imports all of the above; removed the duplicated
  getCategoryColorHex, stats helpers, branch id/label lists, and inline magic numbers
- Populated src/lib/index.ts barrel

Bug fixes:
- data.ts: tmdbAPI pypiUrl pointed at tvdbAPI -> corrected to tmdbAPI
- Removed/ gated stray console.log noise (skill-tree-loaded, SW logs)
- Removed dead vars (maxAlpha, glowMaxAlpha) and unused catch binding

Tooling: ESLint + Prettier now clean; added Vitest unit tests for the new
pure utils (14 tests). svelte-check: 0 errors. build: ok.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

static/service-worker.js

@@ -14,30 +14,22 @@ const PRECACHE_ASSETS = [
 
 // Install event - precache critical assets
 self.addEventListener('install', (event) => {
-	console.log('[Service Worker] Installing...');
 	event.waitUntil(
 		caches.open(CACHE_NAME)
-			.then((cache) => {
-				console.log('[Service Worker] Precaching assets');
-				return cache.addAll(PRECACHE_ASSETS);
-			})
+			.then((cache) => cache.addAll(PRECACHE_ASSETS))
 			.then(() => self.skipWaiting())
 	);
 });
 
 // Activate event - clean up old caches
 self.addEventListener('activate', (event) => {
-	console.log('[Service Worker] Activating...');
 	event.waitUntil(
 		caches.keys()
 			.then((cacheNames) => {
 				return Promise.all(
 					cacheNames
 						.filter((name) => name !== CACHE_NAME && name !== RUNTIME_CACHE)
-						.map((name) => {
-							console.log('[Service Worker] Deleting old cache:', name);
-							return caches.delete(name);
-						})
+						.map((name) => caches.delete(name))
 				);
 			})
 			.then(() => self.clients.claim())