feat(node): add TypeScript sibling project for npm-based install

Introduces @kuns/claude-mailbox under node/, a wire-compatible TypeScript
port of the .NET daemon that distributes via the public Gitea npm registry.
The .NET project stays in src/ClaudeMailbox/ untouched; users pick whichever
flavor they prefer.

- node/ project: fastify + @modelcontextprotocol/sdk StreamableHTTPServerTransport
  + better-sqlite3, schema and wire surface match the C# version (port 47822,
  X-Mailbox header, MCP tool names, snake_case SQLite columns)
- Cross-platform autostart: Scheduled Task (Win, no admin) / Windows Service
  (Win, --service) / launchd (mac) / systemd --user (linux)
- 9/9 vitest tests pass; end-to-end /health + send/check round-trip verified
- CI split: existing ci.yml/release.yml renamed to *-dotnet.yml with path
  filters, new ci-node.yml and release-node.yml publish to Gitea npm registry
- install.ps1 / install.sh bootstrap one-liners at repo root; homebrew/
  contains a tap formula template
- README install section reordered: npm path primary, dotnet publish secondary

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

node/package.json

@@ -0,0 +1,55 @@
+{
+  "name": "@kuns/claude-mailbox",
+  "version": "0.0.0",
+  "description": "Standalone MCP mail server that lets parallel Claude sessions coordinate with each other.",
+  "type": "module",
+  "bin": {
+    "claude-mailbox": "dist/cli.js"
+  },
+  "files": [
+    "dist",
+    "README.md",
+    "LICENSE"
+  ],
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "start": "node dist/cli.js serve",
+    "prepack": "npm run build"
+  },
+  "engines": {
+    "node": ">=20"
+  },
+  "dependencies": {
+    "@modelcontextprotocol/sdk": "^1.29.0",
+    "better-sqlite3": "^11.3.0",
+    "commander": "^12.1.0",
+    "fastify": "^5.0.0",
+    "zod": "^3.25.0"
+  },
+  "optionalDependencies": {
+    "node-windows": "^1.0.0-beta.8"
+  },
+  "devDependencies": {
+    "@types/better-sqlite3": "^7.6.11",
+    "@types/node": "^22.7.4",
+    "typescript": "^5.6.2",
+    "vitest": "^2.1.1"
+  },
+  "keywords": [
+    "mcp",
+    "model-context-protocol",
+    "claude",
+    "mailbox",
+    "ipc"
+  ],
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://git.kuns.dev/releases/ClaudeMailbox.git"
+  },
+  "publishConfig": {
+    "registry": "https://git.kuns.dev/api/packages/releases/npm/"
+  }
+}