feat(development): add development testing setup 🤓

- Add documentation for testing development rules
- Add configuration examples for excluding unwanted rules during testing
- Add development deno.json with plugin configuration and rule exclusions
- Add development README with testing instructions and configuration guide
- Add problematic.ts test file with sample code violating multiple lint rules

Author: NeaByteLab

development/README.md

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+# Development Rules Testing
+
+This directory contains development files for testing additional lint rules that leverage Deno's full AST capabilities to fill gaps in the official Deno rules. See [DENO-RULES.md](./DENO-RULES.md) for a complete reference of all official Deno lint rules.
+
+These rules leverage Deno's amazing AST capabilities to provide enhanced auto-fix functionality with better performance than traditional LSP-based approaches, offering more customization opportunities for developers.
+
+## ⚠️ Important Note
+
+> **Known Issue**: Due to [Deno issue #31017](https://github.com/denoland/deno/issues/31017), the `include` configuration in `deno.json` rules section doesn't work for plugin rules. Only `exclude` works. This forces you to load all plugin rules and then disable unwanted ones until the issue is resolved.
+
+## 📋 How to Test
+
+### 1. Configure Rules to Test
+
+Edit `deno.json` and add rules you don't want to test into the `exclude` section:
+
+```json
+{
+  "lint": {
+    "rules": {
+      "exclude": [
+        "deno-lint/prefer-early-return",
+        "deno-lint/explicit-parameter-types"
+        // Exclude any rules you don't want to use
+      ]
+    }
+  }
+}
+```
+
+> **Note**: You should use `exclude` instead of `include` due to the aforementioned Deno limitation.
+
+### 2. Write Problematic Code
+
+Create test files with problematic code related to the rules you want to test. This is like regular code that intentionally violates the lint rules to verify they work correctly. Consider mixing problematic code with other valid code to catch more bugs and edge cases.
+
+**Example**: See `problematic.ts` for reference.
+
+### 3. Run Linting
+
+Navigate to the development directory and run:
+
+```bash
+cd development
+deno lint problematic.ts
+```
+
+For automatic fixes:
+
+```bash
+deno lint problematic.ts --fix
+```

development/deno.json

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+{
+  "links": [".."],
+  "lint": {
+    "plugins": ["jsr:@neabyte/deno-lint@0.2.1"],
+    "rules": {
+      "exclude": [
+        "deno-lint/async-function-naming",
+        "deno-lint/explicit-parameter-types",
+        "deno-lint/explicit-return-types",
+        "deno-lint/prefer-const-assertions",
+        "deno-lint/prefer-nullish-coalescing",
+        "deno-lint/prefer-optional-chain",
+        "deno-lint/prefer-template-literals",
+        "deno-lint/prefer-early-return",
+        "deno-lint/prefer-promise-reject-errors",
+        "deno-lint/require-error-handling"
+      ]
+    }
+  }
+}

development/problematic.ts

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+// Write problematic code here
+
+// Missing return type annotation
+function getUserData(id: string) {
+  return { id, name: 'John' }
+}
+
+// Missing parameter type annotation
+function processData(data) {
+  return data.toString()
+}
+
+// Using logical OR instead of nullish coalescing
+const result = user?.name || 'default'
+
+// Missing async suffix
+async function fetchData() {
+  return await fetch('/api/data')
+}
+
+// Nested if statements (should use early return)
+function validateUser(user) {
+  if (user) {
+    if (user.isActive) {
+      if (user.role === 'admin') {
+        return true
+      }
+    }
+  }
+  return false
+}
+
+// Missing const assertion
+const config = { apiUrl: 'https://api.example.com' }
+
+// Promise.reject without Error object
+Promise.reject('Something went wrong')
+
+// Export to avoid "no unused variable" warnings
+export { getUserData, processData, fetchData, validateUser, config, result }