chore: add CI, coverage gates, and fix template hygiene

Wires the previously-inert @vitest/coverage-v8 into the test builder with
measured thresholds, adds a GitHub Actions workflow (format, test, build),
and fixes assorted gaps a cloning team would hit: no LICENSE, no engines/
.nvmrc, an unusable prettier install, a committed local-only settings file,
a dead 0-byte stylesheet, and a broken Karma-era VS Code test/debug config.
Also drops @angular/forms, which nothing in src/ imports.

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

.vscode/launch.json

@@ -8,13 +8,6 @@
       "request": "launch",
       "preLaunchTask": "npm: start",
       "url": "http://localhost:4200/"
-    },
-    {
-      "name": "ng test",
-      "type": "chrome",
-      "request": "launch",
-      "preLaunchTask": "npm: test",
-      "url": "http://localhost:9876/debug.html"
     }
   ]
 }