PERF.58 Apps: an installed add-on package is relinked from blob modules on every start (hvac 334 ms, plant 756 ms) and ships as base64 JSON

addons.js linkPackage turns each verified package into blob: module URLs every start: hvac 0.9.0 (193 files, 1.8 MB; 2.4 MB as base64 JSON) costs 334 ms per start (link 115, import 55, verify 6); plant 756 ms (import 447). The Ed25519 plus sha256 check is cheap (6 to 11 ms for 100 to 193 files); blob modules get no HTTP cache and no V8 code cache, so the cost repeats on every visit and grows with file count. Change: keep the signature check but serve verified packages from the service worker under a stable /addons/pkg/<sha>/<path> scope (or cache the linked texts and import() a persistent URL) so modules get code caching; stop base64 in the package JSON (binary zip, about 34 % smaller). AddonPackages.php, addons.js, sw.js.