fix(icons): commit generated icons; installs and regular builds never render

User installs failed with 'resvg-py is missing' because the web/desktop
source builds rendered icons on whatever python was on PATH. The default
brand outputs are now committed; source_build, apps/desktop build.mjs and
the npm/docusaurus pre-hooks consume them directly. Flavored release
bundles (canary/commit) still render into their own product dir.

icons-freshness-check now regenerates and fails on any byte diff.

web/package.json

@@ -4,9 +4,7 @@
   "version": "0.0.0",
   "type": "module",
   "scripts": {
-    "predev": "node ../scripts/generate-icons.mjs --source .. --out ..",
     "dev": "vite",
-    "prebuild": "node ../scripts/generate-icons.mjs --source .. --out ..",
     "build": "node ../scripts/build/web.mjs",
     "lint": "eslint .",
     "lint:fix": "eslint . --fix",