feat(web-test): embed browser automation engine into skill

Move browser.mjs, dom.mjs, run.mjs from external 1c-web-client-mcp
project into .claude/skills/web-test/scripts/. Now the skill is
self-contained — copy .claude/skills/ + npm install is all that's
needed.

- Add scripts/package.json with playwright dependency
- Update SKILL.md with relative runner path and setup section
- Add node_modules/ and .browser-session.json to .gitignore

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

.gitignore

@@ -18,3 +18,7 @@ tools/
 
 # Локальный реестр баз данных 1С
 .v8-project.json
+
+# web-test: Node.js зависимости и runtime
+.claude/skills/web-test/scripts/node_modules/
+.claude/skills/web-test/.browser-session.json