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>

scripts/code_language_allow.txt

@@ -0,0 +1,15 @@
+# Words only this repository may use, in addition to the dashboard's
+# scripts/code_language_allow.txt. Format: `path::word` (bound to one path or
+# path prefix) or a bare word (anywhere). Each entry says why.
+#
+# The .fls format is Java's XMLEncoder output: its class and property names
+# (filius.hardware.knoten.Vermittlungsrechner, GUIKnotenItem, ipAdresse …)
+# are fields of a foreign API and keep their German names — in packages/fls
+# only.
+#
+# Java FILIUS class and package names, cited in the provenance header of each
+# ported file and in comments that point at the Java behaviour they copy.
+vermittlungsrechner
+verbindung
+netzzugangsschicht
+vermittlungsschicht