Bootstrap the TypeScript workspace and standalone runtime

[codeacme17]

Tracks #1.

Summary

Bootstrap the smallest runnable TypeScript workspace that can host the launcher, local server, React surface, Repository Engine, shared protocol, and two Host Adapters without implementing Git product behavior yet.

Scope

• Require Node.js 22 and use npm workspaces.
• Create apps/launcher, apps/server, and apps/ui.
• Create packages/protocol, packages/repository-engine, and packages/host-adapter with codex-cdp and standalone adapters.
• Add TypeScript, React/Vite, Vitest, formatting, linting, type-checking, build, and test scripts.
• Add one health endpoint and one placeholder Git Surface reachable through the standalone adapter.
• Establish contract, integration, and end-to-end test directories plus a temporary Git fixture helper.
• Keep composition roots thin and avoid speculative ports with only one implementation.

Acceptance criteria

• A fresh checkout installs, type-checks, tests, and builds using documented commands.
• npm run dev starts the local placeholder surface through the standalone adapter.
• npm test executes at least one test through each intended test layer.
• The Repository Engine package exposes only the planned session boundary; it contains no Git behavior yet.
• The UI cannot import Node filesystem or child-process modules.
• No Tauri dependency or Codex DOM selector is introduced in this bootstrap issue.

Out of scope

• Codex injection, Git discovery, Git mutations, packaging, or product styling.

Dependencies

• Add the decision-complete MVP product and architecture documentation #2 should land first so repository terminology and architecture are available during review.

Verification

• Clean install, type-check, unit test, production build, and standalone smoke test on macOS.