feat(core): event queue, Ethernet, switch, ARP, IPv4, ICMP, routing and firewall

First slice of the TypeScript port of the filius-ipad runtime engine,
with 29 tests ported from the Swift suite. Parts not ported yet throw
NotPortedError instead of guessing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -1,14 +1,7 @@
-# ---> VisualStudioCode
+node_modules/
+dist/
+coverage/
+*.tsbuildinfo
 .vscode/*
 !.vscode/settings.json
-!.vscode/tasks.json
-!.vscode/launch.json
 !.vscode/extensions.json
-!.vscode/*.code-snippets
-
-# Local History for Visual Studio Code
-.history/
-
-# Built Visual Studio Code Extensions
-*.vsix
-