feat(test): WP-46 — Vitest coverage (report-only)

Enable coverage via the @angular/build:unit-test builder's first-class options: a
`coverage` configuration on the test target (v8 provider, text-summary/html/lcov,
excludes for specs/stories/contracts/generated client) + `npm run test:coverage`.
Report-only (no thresholds) — visibility first. CI's test step now runs test:coverage
(strict superset: fails on a failing test, never on coverage). Baseline ~71% stmts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package-lock.json

@@ -33,6 +33,7 @@
         "@storybook/addon-onboarding": "^10.4.6",
         "@storybook/angular": "^10.4.6",
         "@storybook/test-runner": "^0.24.4",
+        "@vitest/coverage-v8": "^4.1.9",
         "angular-eslint": "^22.0.0",
         "axe-playwright": "^2.2.2",
         "concurrently": "^10.0.3",
@@ -10409,6 +10410,92 @@
         "vite": "^6.0.0 || ^7.0.0 || ^8.0.0"
       }
     },
+    "node_modules/@vitest/coverage-v8": {
+      "version": "4.1.9",
+      "resolved": "https://registry.npmjs.org/@vitest/coverage-v8/-/coverage-v8-4.1.9.tgz",
+      "integrity": "sha512-G9/lgqibheLVBDRuya45EbsEXTYcWoSG+TLg7i2axuzx0Eq62eXn+aWXyaVdV5vKvFSWd6ywcX8hA7la9Pvu8g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@bcoe/v8-coverage": "^1.0.2",
+        "@vitest/utils": "4.1.9",
+        "ast-v8-to-istanbul": "^1.0.0",
+        "istanbul-lib-coverage": "^3.2.2",
+        "istanbul-lib-report": "^3.0.1",
+        "istanbul-reports": "^3.2.0",
+        "magicast": "^0.5.2",
+        "obug": "^2.1.1",
+        "std-env": "^4.0.0-rc.1",
+        "tinyrainbow": "^3.1.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/vitest"
+      },
+      "peerDependencies": {
+        "@vitest/browser": "4.1.9",
+        "vitest": "4.1.9"
+      },
+      "peerDependenciesMeta": {
+        "@vitest/browser": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@vitest/coverage-v8/node_modules/@bcoe/v8-coverage": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/@bcoe/v8-coverage/-/v8-coverage-1.0.2.tgz",
+      "integrity": "sha512-6zABk/ECA/QYSCQ1NGiVwwbQerUCZ+TQbp64Q3AgmfNvurHH0j8TtXa1qbShXA6qqkpAj4V5W8pP6mLe1mcMqA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@vitest/coverage-v8/node_modules/@vitest/pretty-format": {
+      "version": "4.1.9",
+      "resolved": "https://registry.npmjs.org/@vitest/pretty-format/-/pretty-format-4.1.9.tgz",
+      "integrity": "sha512-s0iufns3iIFitdgm+YR7g1whCAaGtXz459VS9/PqyKDEEFgYIhsHOQmXgIgDuYCt7DeQmiZT0Qe2OA2p4ZPu5A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "tinyrainbow": "^3.1.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/vitest"
+      }
+    },
+    "node_modules/@vitest/coverage-v8/node_modules/@vitest/utils": {
+      "version": "4.1.9",
+      "resolved": "https://registry.npmjs.org/@vitest/utils/-/utils-4.1.9.tgz",
+      "integrity": "sha512-A51o8ymO5PpqlWNnBP9ZHPXDIpuMtTLlGSjN7la4US+LJzoUMyhwjA5QXlm39JexgwHKW4Xjs8Z2d3dLCXOeuA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@vitest/pretty-format": "4.1.9",
+        "convert-source-map": "^2.0.0",
+        "tinyrainbow": "^3.1.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/vitest"
+      }
+    },
+    "node_modules/@vitest/coverage-v8/node_modules/convert-source-map": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-2.0.0.tgz",
+      "integrity": "sha512-Kvp459HrV2FEJ1CAsi1Ku+MY3kasH19TFykTz2xWmMeq6bk2NU3XXvfJ+Q61m0xktWwt+1HSYf3JZsTms3aRJg==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@vitest/coverage-v8/node_modules/tinyrainbow": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/tinyrainbow/-/tinyrainbow-3.1.0.tgz",
+      "integrity": "sha512-Bf+ILmBgretUrdJxzXM0SgXLZ3XfiaUuOj/IKQHuTXip+05Xn+uyEYdVg0kYDipTBcLrCVyUzAPz7QmArb0mmw==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=14.0.0"
+      }
+    },
     "node_modules/@vitest/expect": {
       "version": "3.2.4",
       "resolved": "https://registry.npmjs.org/@vitest/expect/-/expect-3.2.4.tgz",
@@ -11241,6 +11328,25 @@
         "node": ">=4"
       }
     },
+    "node_modules/ast-v8-to-istanbul": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/ast-v8-to-istanbul/-/ast-v8-to-istanbul-1.0.5.tgz",
+      "integrity": "sha512-UPAgKJFSEGMWSDr3LX4tqnAb4f7KGT8O40Tyx8wbYmmZ/yn58lNCm8h3svs3eXgiGd5AXxz8NDOvXWvicq+rJA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@jridgewell/trace-mapping": "^0.3.31",
+        "estree-walker": "^3.0.3",
+        "js-tokens": "^10.0.0"
+      }
+    },
+    "node_modules/ast-v8-to-istanbul/node_modules/js-tokens": {
+      "version": "10.0.0",
+      "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-10.0.0.tgz",
+      "integrity": "sha512-lM/UBzQmfJRo9ABXbPWemivdCW8V2G8FHaHdypQaIy523snUjog0W71ayWXTjiR+ixeMyVHN2XcpnTd/liPg/Q==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/async": {
       "version": "3.2.6",
       "resolved": "https://registry.npmjs.org/async/-/async-3.2.6.tgz",
@@ -18686,6 +18792,18 @@
         "@jridgewell/sourcemap-codec": "^1.5.5"
       }
     },
+    "node_modules/magicast": {
+      "version": "0.5.3",
+      "resolved": "https://registry.npmjs.org/magicast/-/magicast-0.5.3.tgz",
+      "integrity": "sha512-pVKE4UdSQ7DvHzivsCIFx2BJn1mHG6KsyrFcaxFx6tONdneEuThrDx0Cj3AMg58KyN4pzYT+LHOotxDQDjNvkw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@babel/parser": "^7.29.3",
+        "@babel/types": "^7.29.0",
+        "source-map-js": "^1.2.1"
+      }
+    },
     "node_modules/make-dir": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/make-dir/-/make-dir-4.0.0.tgz",