feat: v1.1 portable architecture (app/data separation)

New directory structure:
- app/core/ = OpenClaw program
- app/runtime/ = Node.js
- data/ = user config, memory, backups (never overwritten on upgrade)
- system/ = migration scripts

Features:
- Auto port detection (18789-18799)
- macOS Gatekeeper auto-fix (xattr quarantine removal)
- Windows UTF-8 BOM + CRLF encoding
- Config auto-migration on startup
- Platform-specific packages (Mac ARM64 + Windows x64)

portable/default-config.json

@@ -0,0 +1,6 @@
+{
+  "gateway": {
+    "mode": "local",
+    "auth": { "token": "uclaw" }
+  }
+}