feat(project-editor): add field-schema registry + test harness

Milestone 1 of the Configuration Engine sprint.

- Add schema/ registry: FieldSchema model, SECTION_FIELD_SCHEMAS covering
  every editable field per section, and EditorSchemaService (getFields,
  getField, all, getByPath). Single source of truth for labels, defaults,
  and validator references; sections stay hand-authored (metadata-augmented).
- Stand up Karma + Jasmine (ng test) with a headless, sandbox-free Chrome
  launcher; add tsconfig.spec.json, karma.conf.js, angular.json test target,
  and npm "test" script. First spec: editor-schema.service.spec (7 passing).

No behavior change. Gate: arch:check, tsc --noEmit, npm test (7/7), build all green.

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

package.json

@@ -8,6 +8,7 @@
     "start:dexar": "ng serve --configuration=development --port 4200",
     "build": "ng build",
     "build:dexar": "ng build --configuration=production",
+    "test": "ng test --watch=false --browsers=ChromeHeadlessNoSandbox",
     "watch": "ng build --watch --configuration development",
     "arch:check:boundaries": "node tools/architecture/check-boundaries.mjs",
     "arch:check:cycles": "npx --yes madge --circular --extensions ts src/app --ts-config tsconfig.app.json",
@@ -39,6 +40,12 @@
     "@angular/build": "21.1.5",
     "@angular/cli": "21.1.5",
     "@angular/compiler-cli": "21.1.5",
+    "@types/jasmine": "~5.1.0",
+    "jasmine-core": "~5.5.0",
+    "karma": "~6.4.0",
+    "karma-chrome-launcher": "~3.2.0",
+    "karma-jasmine": "~5.1.0",
+    "karma-jasmine-html-reporter": "~2.1.0",
     "typescript": "~5.9.3",
     "barry-cache": "^0.1.0"
   }