fix(ios): Pin SnapshotPreviews (#796)

Pin the `SnapshotPreviews` Swift package dependency to the semantic
version range `0.13.0..<1.0.0` instead of tracking the upstream `main`
branch.

Tracking `main` meant each resolve could pull in unreviewed upstream
changes, making builds non-reproducible and leaving snapshot tests
vulnerable to breakage from dependency drift. Pinning to a version range
keeps future updates explicit and reviewable while still allowing
non-breaking upgrades within the 0.x line.

Resolved revision moves from `ee693c3` (unversioned `main`) to `83131a5`
(tag `0.13.0`).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: cameroncooke

ios/HackerNews.xcodeproj/project.pbxproj

@@ -1271,8 +1271,9 @@
 			isa = XCRemoteSwiftPackageReference;
 			repositoryURL = "https://github.com/EmergeTools/SnapshotPreviews";
 			requirement = {
-				branch = main;
-				kind = branch;
+				kind = versionRange;
+				maximumVersion = 1.0.0;
+				minimumVersion = 0.13.0;
 			};
 		};
 		F48E9EC92D4D691600FD8B30 /* XCRemoteSwiftPackageReference "ETDistribution" */ = {