chore: fix monorepo build pipeline and migrate shared to built package

- Root package.json: add workspace scripts (dev, build, test, test:cov, test:e2e)
  that delegate to actual scripts in shared/server/client workspaces
- shared: add tsup build step (CJS + ESM dual output, .d.ts); consumers now import
  from the built dist instead of raw TS source via path aliases
- server: replace tsc-alias with tsconfig-paths (tsc-alias mangled node_modules
  paths); fix MCP SDK path aliases to point to root node_modules (../node_modules)
- server/scripts/dev.mjs: delay node --watch until tsc -w signals first-pass done,
  eliminating the spurious restart on every dev startup
- client/vite.config.js + vitest.config.ts: remove @trek/shared path alias (no longer
  needed now that shared is a proper package)
- Consolidate package-lock.json at the workspace root; drop per-workspace lock files

client/vitest.config.ts

@@ -1,19 +1,8 @@
 import { defineConfig } from 'vitest/config';
 import react from '@vitejs/plugin-react';
-import { fileURLToPath } from 'node:url';
 
 export default defineConfig({
   plugins: [react()],
-  resolve: {
-    alias: {
-      // @trek/shared — Zod contract package (tests resolve it to TS source,
-      // mirroring the alias in vite.config.js used by the dev server / build).
-      '@trek/shared': fileURLToPath(new URL('../shared/src/index.ts', import.meta.url)),
-    },
-    // Mirror vite.config.js: keep a single zod instance resolvable from the
-    // shared source, which lives outside this project root.
-    dedupe: ['zod'],
-  },
   test: {
     root: '.',
     globals: true,