chore: bump cursor_templates_version to 1.0.4 and update related files

- Updated cursor_templates_version in project-brief.yaml to 1.0.4 for reproducibility.
- Enhanced CHANGELOG with fixes and features for version 1.0.4, including improved template resolution for global installs.
- Updated pubspec.yaml and VERSION file to reflect the new version.
- Added new templates for AGENTS.md and lefthook.yaml to the generator.
- Adjusted tests to include new root-level files in the output.

This release addresses template resolution issues and introduces new repo-level configuration files.

flutter-cursor-templates/templates/root/AGENTS.md.tmpl

@@ -0,0 +1,5 @@
+# {{PROJECT_NAME}}
+
+Repo-level notes for AI assistants. Authoritative stack and conventions are in `project-brief.yaml` and `.cursor/` (regenerate with `cursor_gen` from the project root).
+
+- **Package:** `{{PACKAGE_ID}}`

flutter-cursor-templates/templates/root/lefthook.yaml.tmpl

@@ -0,0 +1,5 @@
+# {{PROJECT_NAME}} — generated by cursor_gen; adjust commands to your repo
+pre-commit:
+  commands:
+    flutter-analyze:
+      run: flutter analyze