New src/cli/ module providing a headless CLI for AI agents to work with
Overleaf projects from a server with no display. Commands: auth, projects,
clone, pull, status, push, compile.

Key design decisions:
- Uses Node.js https module (no Electron dependency), same approach as the
  existing MCP server in src/mcp/lattex.mjs
- Reuses overleafProtocol.ts for Socket.IO v0.9 parsing (pure, no Electron)
- Separate esbuild bundle (out/cli/lattex-cli.mjs) — does not touch the
  Electron app build
- 64 tests for arg parsing, file tree walking, diff logic, and log parsing

Files:
- src/cli/main.ts — CLI entry point with all commands
- src/cli/args.ts — argument parser
- src/cli/overleafApi.ts — Overleaf API client using https + ws
- src/cli/fileTree.ts — project root folder walker
- src/cli/localState.ts — per-clone state (.lattex-cli.json) and auth storage
- src/cli/diff.ts — local vs remote diff logic
- src/cli/logParser.ts — LaTeX compile log parser
- src/cli/test.ts — unit tests
- tsconfig.cli.json — TypeScript config for CLI

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>