Expand repo rules to include style guide and UI development guidelines (#9754)

* Expand repo rules to include style guide and UI development guidelines

* include utils

* add guidance for integration tests

Author: kenzieschmoll

AI_RULES.md

@@ -0,0 +1,36 @@
+# DevTools Repo Guidelines for AI Assistants
+
+Follow these rules when working in this repository.
+
+## Repository Rules
+
+### Dependencies
+-   **`packages/devtools_shared`**: Never introduce a Flutter dependency or a dependency on web-only Dart libraries.
+-   **Imports**: Never import `packages/devtools_app/lib/devtools_app.dart` in code under `packages/devtools_app/lib/src/`. It is acceptable in test code.
+
+### Code Style
+-   **Style Guide**: Follow the DevTools style guide in [STYLE.md](STYLE.md).
+-   **Formatting & Analysis**: Always ensure code is formatted properly and has no analysis errors or warnings before completing a task.
+
+## Running Tests
+
+-   **Standard Packages**: Run unit and widget tests with `flutter test`.
+-   **`packages/devtools_shared`**: Run tests with `dart test`.
+-   **Integration Tests**: Refer to the [Integration Test README](packages/devtools_app/integration_test/README.md) for instructions on running integration tests.
+
+## Tooling Best Practices
+
+-   **MCP Tools**: Prefer using MCP server tools over shell commands whenever possible.
+
+## UI Development Guidelines
+
+### Constants and Magic Values
+-   **Avoid Raw Values**: Avoid using raw strings or numbers in UI code. Use named constants instead.
+
+### Themes and Styles
+-   **Use Existing Themes**: Use existing theme values and text styles from `packages/devtools_app_shared/lib/src/ui/theme/theme.dart` (e.g., `Theme.of(context).regularTextStyle`).
+-   **Reuse Patterns**: Reuse common patterns and styles used in other UI code in the repository.
+
+### Code Reuse
+-   **Use Shared Components & Utils**: Prefer using reusable components from `shared/ui/` (such as `packages/devtools_app/lib/src/shared/ui/common_widgets.dart`), primitives from `shared/primitives/`, and utilities from `shared/utils/` rather than creating things from scratch.
+

GEMINI.md

@@ -1,24 +1,3 @@
-# Repository rules
-
-When making changes to this code base, follow these rules, which are listed
-in no particular order:
-- `packages/devtools_shared` should never introduce a Flutter dependency or a
-dependency on web-only Dart libraries.
-- never import the `packages/devtools_app/lib/devtools_app.dart` file in code
-that lives under `packages/devtools_app/lib/src/`. This file is okay to import
-in code that lives under `packages/devtools_app/test/`.
-
-# Running tests
-
-Unit test and widget tests are all contained under a package's `test/`
-directory. These tests should be run with `flutter test` in all packages except
-for `packages/devtools_shared`, whose tests should be run with `dart test`.
-
 # Gemini Guidelines
 
-- Prefer to use MCP server tools over shell commands whenever possible.
-- When you are done making code changes, ensure the code does not have analysis
-errors or warnings. Also ensure it is formatted properly. You should have MCP
-server tools available to you to perform these tasks. If not, you can get
-analysis errors and warnings by running the `dart analyze` shell command, and
-you can perform Dart formatting with the `dart format` shell command.
+Refer to the shared [AI Rules](AI_RULES.md) for guidelines when working in this repository.