feat(add): wire Angular, Vue and SvelteKit web apps

[Bccorb]

Closes #248. The last half of it: seamless add now wires Angular, Vue and SvelteKit web apps on the new @seamless-auth/angular (0.2.0), @seamless-auth/vue and @seamless-auth/svelte (0.1.0) bindings, beside React.

What changes

• Detection:
  • Angular from @angular/core. The entry is app.config.ts, then app.module.ts, then main.ts.
  • Vue from vue, excluding Nuxt. It also finds the file the router is created in.
  • SvelteKit from @sveltejs/kit. Kit 3 imports from #lib, Kit 2 from $lib.
  • Missing router peers (vue-router, @angular/router) are installed with the binding.
  • Nuxt and Svelte without SvelteKit are reported, not wired. The bindings need SvelteKit's navigator, or one written for another router.
• Env:
  • Vue and SvelteKit get VITE_API_URL in .env.local.
  • Angular's CLI does not read .env, so no file is written and the backend URL goes in the printed provideSeamlessAuth call.
  • The default web origin for CORS is 4200 for Angular.
• Printed code, one step per file:
  • Angular: providers with the interceptor in app.config.ts, then seamlessAuthRoutes with authGuard and guestGuard in app.routes.ts.
  • Vue: createSeamlessAuthRoutes() and guards in the router file, then app.use(createSeamlessAuth(...)). An app with no vue-router gets a whole router, plus a reminder to render <RouterView />.
  • SvelteKit: src/lib/auth, ssr = false plus the root layout's session and navigator, then the eight screen pages with requireAuth and requireGuest loads.
  • The SvelteKit 3 import is #lib/auth.js: Kit 3 maps #lib/* to src/lib/* as written, so svelte-check cannot resolve it without the extension.
• The web output moves into src/core/webSnippets.ts. README, seamless help add and a minor changeset are updated. The "does not wire yet" line no longer points at feat(add): add Seamless Auth to existing Go, Rust, Python, Angular, Vue and Svelte projects #248.

Verification

• Scaffolded apps: I generated a fresh app with each official scaffolder: ng new (Angular 22), create-vue --ts --router, and sv create (SvelteKit 3). Each was paired with an Express backend.
• Pasting and building: I ran seamless add --local on each and pasted the printed code into the app. Each build passed: ng build, vue-tsc plus vite build, and svelte-check plus vite build.
• Browser sign-in, on all three:
  1. A visit to / was guarded and redirected to /login.
  2. Registering by email sent the one-time code, which printed in the backend console.
  3. Entering the code worked, and skipping the passkey prompt led to the signed-in page.
  4. /api/me returned 200.
  5. Logout went to /login, and /api/me then returned 401.
• Vue without vue-router (create-vue --ts with no router): vue-router was installed, and the printed whole-router code type-checks and builds.
• Tests: npm test passed 1265 tests. Coverage is 98.81 statements, 96.14 branches and 99.23 lines.