Drop quotesu/ setup doc; make the demo take any sicd host as an argument

The quotesu setup notes exposed internal host details and aren't useful to
readers, so remove the directory. The quoting-hell demo now requires the
target host as an argument (any host running sicd) instead of defaulting to
an internal name, and its labels say sic rather than the old rs. Example
hostnames in the README/SKILL/main.go are now the neutral placeholder host1.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWpfhDgYNA21tETDP9ueBE

cmd/sic/main.go

@@ -11,9 +11,9 @@
 //
 // Examples:
 //
-//	sic quotesu echo hello world
-//	sic quotesu touch 'a b'         # ONE file, not two
-//	sic --sh quotesu 'echo hi | wc -c'
+//	sic host1 echo hello world
+//	sic host1 touch 'a b'         # ONE file, not two
+//	sic --sh host1 'echo hi | wc -c'
 package main
 
 import (