feat: self-heal Electron installs before dev and postinstall

Adds an Electron install check that repairs incomplete or wrong-architecture binaries
Runs the check during root postinstall and before electron dev startup
Adds tests and docs for the new ensure:electron workflow

package.json

@@ -40,7 +40,7 @@
     "lint:mobile": "bun run --cwd packages/mobile lint",
     "clean": "bun run --filter '*' clean",
     "changelog-card": "node scripts/changelog-card/generate.mjs",
-    "postinstall": "node ./fix-deprecation.js && patch-package",
+    "postinstall": "node ./fix-deprecation.js && patch-package && node ./packages/electron/scripts/ensure-electron.mjs --best-effort",
     "dev:web": "bun run --cwd packages/web build:watch",
     "dev:web:server": "bun run --cwd packages/web dev:server:watch",
     "dev:web:full": "node ./scripts/dev-web-full.mjs",