Add builder service: scaffold, ASC API, devices UI, fastlane profile manager

Phase 1-3 of the builder subsystem on the Mac mini:
- Express + SQLite + sessions scaffolding, LAN-only service on port 3090
- App Store Connect JWT client (ES256 signing, devices/profiles/bundleIds)
- Device management UI with Apple-side registration
- Fastlane sigh wrapper with profile cache + auto-install to ~/Library/
- launchd plist + deploy script for Mac mini supervision

builder/.env.example

@@ -0,0 +1,14 @@
+# Web UI password
+ADMIN_PASSWORD=changeme
+
+# Session secret
+SESSION_SECRET=changeme-random-string
+
+# Data directory (where SQLite, source archives, builds, profiles live)
+DATA_DIR=/Users/m4mini/AppStoreBuilder/data
+
+# Port
+PORT=3090
+
+# Shared secret for enrollment callbacks from the unraid container
+BUILDER_SHARED_SECRET=changeme-same-as-unraid-env