chore(tsconfig): enable strict + strictTemplates

Adds the `strict` umbrella flag (on top of the existing individual flags) and
Angular's `strictTemplates`. Build and full test suite pass with no new errors.

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

tsconfig.json

@@ -3,6 +3,7 @@
 {
   "compileOnSave": false,
   "compilerOptions": {
+    "strict": true,
     "noImplicitOverride": true,
     "noPropertyAccessFromIndexSignature": true,
     "noImplicitReturns": true,
@@ -26,7 +27,8 @@
   "angularCompilerOptions": {
     "enableI18nLegacyMessageIdFormat": false,
     "strictInjectionParameters": true,
-    "strictInputAccessModifiers": true
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
   },
   "files": [],
   "references": [