fix: review pass — package.json version, import dedup, error context, stale help

Findings from /review on the wave PR:

- [P1] package.json version was 0.18.0.1 but VERSION is 0.18.1.0, failing
  test/gen-skill-docs.test.ts:177 "package.json version matches VERSION file".
  Bumped package.json to 0.18.1.0.
- [P2] Duplicate import of cookie-picker-routes in browse/src/server.ts
  (handleCookiePickerRoute at line 20 + hasActivePicker at line 792). Merged
  into single import at top.
- [P2] cookie-import-browser.ts:494 generic rethrow loses underlying error.
  Now preserves the message so "ENOENT" vs "JSON parse error" vs "permission
  denied" are distinguishable in user output.
- [P3] setup:46 "Missing value for --host" error message listed an incomplete
  set of hosts (missing factory, openclaw, hermes, gbrain). Aligned with the
  "Unknown value" error on line 94.

Kept as-is (not real issues):
- cookie-import-browser.ts:869 empty catch on Chrome version fetch is the
  correct pattern for best-effort diagnostics (per slop-scan philosophy in
  CLAUDE.md — fire-and-forget failures shouldn't throw).

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "0.18.0.1",
+  "version": "0.18.1.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",