HS E36: socket URL parsing + hs-socket-register! runtime (+3 tests)

- parser.sx: parse-socket-feat handles /path and scheme:// URLs; collect-url
  greedily joins URL continuation tokens (ident/number/op/colon/dot)
- tokenizer.sx: fix :// not treated as line comment (lookback check)
- compiler.sx: emit-socket compiles socket AST to hs-socket-register! call
- runtime.sx: hs-socket-register! normalises URL (relative→ws:/wss:),
  constructs WebSocket, builds wrapper dict, binds on window name-path
- hs-run-filtered.js: WebSocket mock uses plain object (not JS array) so
  host-global returns a foreign value rather than SX list; host-get idx works

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/hyperscript/tokenizer.sx

@@ -441,7 +441,11 @@
               (cond
                 (and (= ch "-") (< (+ pos 1) src-len) (= (hs-peek 1) "-"))
                 (do (hs-advance! 2) (skip-comment!) (scan!))
-                (and (= ch "/") (< (+ pos 1) src-len) (= (hs-peek 1) "/"))
+                (and
+                  (= ch "/")
+                  (< (+ pos 1) src-len)
+                  (= (hs-peek 1) "/")
+                  (not (and (> pos 0) (= (hs-peek -1) ":"))))
                 (do (hs-advance! 2) (skip-comment!) (scan!))
                 (and
                   (= ch "<")