fix(schematics): warn instead of crashing when the post-init firebase.json read fails

The re-read added for the firestore starter files was unguarded, so a
firebase.json that firebase-tools left unreadable would abort the whole
ng add. Before the starter files moved after the init calls, this same
failure degraded gracefully — the files were already staged, and
addFirestoreToFirebaseJson warned and let setup finish. Restore that:
warn and continue. createFirestoreStarterFiles independently checks the
disk for each file it would create, so a missing snapshot costs the
firestore-section check, not the collision safety it also relies on.

Trimmed the surrounding comments to the two constraints a future edit
could silently break — read after init, and run before
addFirestoreToFirebaseJson — and moved the rationale here.

The reason the read sits after the init calls at all: staging against a
stale pre-init snapshot risks the Tree/disk collision the .firebaserc
write hit earlier in this PR, where a Tree-staged file collides at
commit time with one firebase-tools already wrote to disk and aborts the
run. No init call adds a firestore section today, so that specific path
is defensive against a future one.

Author: armando-navarro

src/schematics/setup/index.ts

@@ -147,18 +147,19 @@ export const ngAddSetupProject = (
 
     }
 
-    // Re-read firebase.json after the last firebaseTools.init call — init rewrites it on disk
-    // mid-run, staging files against a stale pre-init copy risks the same Tree/disk collision
-    // .firebaserc hit earlier in this file (a Tree-staged file colliding with one firebase-tools
-    // already wrote to disk, which crashes the schematic when the Tree commits). Right now no
-    // init call adds a firestore section, so this is defensive against a future one that might.
-    const firebaseJsonAfterInit: FirebaseJSON = JSON.parse(
-      readFileSync(join(projectRoot, "firebase.json")).toString()
-    );
-    // Must run before addFirestoreToFirebaseJson below: that call is what adds the firestore
-    // section on a normal run. If it ran first, this read would see the section it just added
-    // and skip creating the files — leaving firebase.json pointing at rules/indexes files that
-    // were never created.
+    // Read after the init calls, never before — firebase-tools rewrites firebase.json on disk
+    // mid-run. A failed read isn't fatal: createFirestoreStarterFiles falls back to checking the
+    // disk for each file it would create.
+    let firebaseJsonAfterInit: FirebaseJSON | undefined;
+    try {
+      firebaseJsonAfterInit = JSON.parse(
+        readFileSync(join(projectRoot, "firebase.json")).toString()
+      );
+    } catch (e) {
+      context.logger.warn(`Could not re-read firebase.json after setup (${e.message}).`);
+    }
+    // Must run before addFirestoreToFirebaseJson: that call adds the firestore section, and if it
+    // ran first this snapshot would see it and skip creating the files it points at.
     createFirestoreStarterFiles(host, context, features, firebaseJsonAfterInit);
 
     // Both write the real filesystem, after the last firebaseTools.init call — init writes