dev: Upgrade Flutter to 3.38.10 and bump dependencies

[offich]

Description

Updated Flutter from 3.29.1 to 3.38.10 and aligned related dependencies to their latest versions.

What was done

• Updated Flutter version from 3.29.1 → 3.38.10 (.fvmrc)
• analyzer: 7.3.0 → 8.4.0
• analyzer_plugin: 0.13.0 → 0.13.10
• custom_lint_builder: 0.7.5 → 0.8.1
• flutter_lints: 5.0.0 → 6.0.0
• pana: 0.22.18 → 0.23.11
• Updated example dependencies:
  • flutter_hooks: 0.21.2 → 0.21.3+1
  • hooks_riverpod: 2.6.1 → 3.1.0
  • riverpod_annotation: 2.6.1 → 4.0.0
  • riverpod_generator: 2.6.5 → 4.0.0+1
  • build_runner: 2.4.15 → 2.15.0
  • custom_lint: 0.7.5 → 0.8.1
• Fixed use_widget_ref_synchronously rule for the version upgrade
• Updated pubspec.lock / example/pubspec.lock

What was NOT done

• Did not add new lint rules
• Did not adopt new features added in Flutter 3.38.10

Operation Confirmation

Prerequisites & Steps

flutter pub get
cd example && dart run custom_lint

Notes & Related URLs

Package	Old Version	New Version	Changelog
analyzer	7.3.0	8.4.0	https://pub.dev/packages/analyzer/changelog
analyzer_plugin	0.13.0	0.13.10	https://pub.dev/packages/analyzer_plugin/changelog
custom_lint_builder	0.7.5	0.8.1	https://pub.dev/packages/custom_lint_builder/changelog
custom_lint	0.7.5	0.8.1	https://pub.dev/packages/custom_lint/changelog
flutter_lints	5.0.0	6.0.0	https://pub.dev/packages/flutter_lints/changelog
pana	0.22.18	0.23.11	https://pub.dev/packages/pana/changelog
flutter_hooks	0.21.2	0.21.3+1	https://pub.dev/packages/flutter_hooks/changelog
hooks_riverpod	2.6.1	3.1.0	https://pub.dev/packages/hooks_riverpod/changelog
riverpod_annotation	2.6.1	4.0.0	https://pub.dev/packages/riverpod_annotation/changelog
riverpod_generator	2.6.5	4.0.0+1	https://pub.dev/packages/riverpod_generator/changelog
build_runner	2.4.15	2.15.0	https://pub.dev/packages/build_runner/changelog