feat(core): drop support for TypeScript 5.9

Drops support for TypeScript 5.9.

BREAKING CHANGE:
* TypeScript versions older than 6.0 are no longer supported.

packages/compiler-cli/package.json

@@ -44,7 +44,7 @@
   },
   "peerDependencies": {
     "@angular/compiler": "0.0.0-PLACEHOLDER",
-    "typescript": ">=5.9 <6.1"
+    "typescript": ">=6.0 <6.1"
   },
   "peerDependenciesMeta": {
     "typescript": {

packages/compiler-cli/src/typescript_support.ts

@@ -16,7 +16,7 @@ import {compareVersions} from './version_helpers';
  * Note: this check is disabled in g3, search for
  * `angularCompilerOptions.disableTypeScriptVersionCheck` config param value in g3.
  */
-const MIN_TS_VERSION = '5.9.0';
+const MIN_TS_VERSION = '6.0.0';
 
 /**
  * Supremum of supported TypeScript versions