Update flutter_lints to 6.0.0 and fix widget tests

- Upgrade flutter_lints from 5.0.0 to 6.0.0
- Fix widget test to reference correct app class (ArcheryBookkeeperApp)
- Update widget test to check for actual app title "Archery Scoring"
- Clean up project description in pubspec.yaml

🤖 Generated with [Claude Code](https://claude.ai/code)

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

pubspec.lock

@@ -66,10 +66,10 @@ packages:
     dependency: "direct dev"
     description:
       name: flutter_lints
-      sha256: "5398f14efa795ffb7a33e9b6a08798b26a180edac4ad7db3f231e40f82ce11e1"
+      sha256: "3105dc8492f6183fb076ccf1f351ac3d60564bff92e20bfc4af9cc1651f4e7e1"
       url: "https://pub.dev"
     source: hosted
-    version: "5.0.0"
+    version: "6.0.0"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -103,10 +103,10 @@ packages:
     dependency: transitive
     description:
       name: lints
-      sha256: c35bb79562d980e9a453fc715854e1ed39e24e7d0297a880ef54e17f9874a9d7
+      sha256: a5e2b223cb7c9c8efdc663ef484fdd95bb243bff242ef5b13e26883547fce9a0
       url: "https://pub.dev"
     source: hosted
-    version: "5.1.1"
+    version: "6.0.0"
   matcher:
     dependency: transitive
     description: