HS runtime: empty/swap/compound events, host-set! fix — 403→423 (51%)

- Fix host-set → host-set! in emit-inc/emit-dec (increment/decrement properties)
- Implement empty/clear command: parser dispatch, compiler, polymorphic runtime
- Implement swap command: parser dispatch, compiler (let+do temp swap pattern)
- Add parse-compound-event-name: joins dot/colon tokens (example.event, htmx:load)
- Add hs-compile to source parser (was only in WASM deploy copy)
- Add clear/swap to tokenizer keywords and cmd-kw? list
- Generator: fix run() with extra args, String.raw support

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/hyperscript/tokenizer.sx

@@ -117,6 +117,8 @@
     "last"
     "random"
     "empty"
+    "clear"
+    "swap"
     "exists"
     "matches"
     "contains"