fix(gen-skill-docs): keep module sync so test require() still works

Two regressions caught by the full test suite after the v1.28.0.0
landing pass:

1) package.json version mismatch — VERSION was bumped to 1.28.0.0
   but package.json still pinned to 1.27.1.0.
   test/gen-skill-docs.test.ts asserts they match.

2) Top-level await in scripts/gen-llms-txt.ts (CLI entry block) and
   scripts/gen-skill-docs.ts (post-step) made gen-skill-docs an
   async module. test/gen-skill-docs.test.ts uses require() to pull
   extractVoiceTriggers/processVoiceTriggers from gen-skill-docs,
   which Bun rejects on async modules with:
     "TypeError: require() async module ... unsupported.
      use 'await import()' instead."

Fix: wrap the await blocks in void IIFEs so the modules remain sync
from a require() perspective.

After fix: all 379 gen-skill-docs tests pass, all 77 new feature
tests pass (3 skipped on macOS — Linux+Xvfb gates).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.27.1.0",
+  "version": "1.28.0.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",