feat: Superpowers for Copilot Chat VS Code extension v1.0.0

- @superpowers chat participant with 14 skill slash commands
- Bundled SKILL.md files for all Superpowers skills
- Custom skill support via ~/.copilot/skills/superpowers/
- Live file watcher — custom skills reload without restart
- TypeScript source: skillLoader, participant, watcher, extension

Skills: brainstorming, tdd, debug, plan, execute, subagent,
parallel, review, receive-review, verify, worktree, finish,
write-skill, superpowers

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.vscodeignore

@@ -0,0 +1,10 @@
+.vscode/**
+src/**
+node_modules/**
+out/test/**
+.gitignore
+.github/**
+tsconfig.json
+**/*.map
+**/*.ts
+!out/**/*.js