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>

angular.json

@@ -25,9 +25,7 @@
                 "input": "public"
               }
             ],
-            "styles": [
-              "src/styles.css"
-            ]
+            "styles": ["src/styles.css"]
           },
           "configurations": {
             "production": {
@@ -66,7 +64,17 @@
           "defaultConfiguration": "development"
         },
         "test": {
-          "builder": "@angular/build:unit-test"
+          "builder": "@angular/build:unit-test",
+          "options": {
+            "coverageExclude": ["src/main.ts", "**/*.spec.ts"],
+            "coverageReporters": ["text-summary", "lcovonly"],
+            "coverageThresholds": {
+              "statements": 90,
+              "branches": 90,
+              "functions": 85,
+              "lines": 95
+            }
+          }
         }
       }
     }