Add comprehensive API v1 with OAuth and API key authentication (#2389)

* OAuth

* Add API test routes and update Doorkeeper token handling for test environment

- Introduced API namespace with test routes for controller testing in the test environment.
- Updated Doorkeeper configuration to allow fallback to plain tokens in the test environment for easier testing.
- Modified schema to change resource_owner_id type from bigint to string.

* Implement API key authentication and enhance access control

- Replaced Doorkeeper OAuth authentication with a custom method supporting both OAuth and API keys in the BaseController.
- Added methods for API key authentication, including validation and logging.
- Introduced scope-based authorization for API keys in the TestController.
- Updated routes to include API key management endpoints.
- Enhanced logging for API access to include authentication method details.
- Added tests for API key functionality, including validation, scope checks, and access control enforcement.

* Add API key rate limiting and usage tracking

- Implemented rate limiting for API key authentication in BaseController.
- Added methods to check rate limits, render appropriate responses, and include rate limit headers in responses.
- Updated routes to include a new usage resource for tracking API usage.
- Enhanced tests to verify rate limit functionality, including exceeding limits and per-key tracking.
- Cleaned up Redis data in tests to ensure isolation between test cases.

* Add Jbuilder for JSON rendering and refactor AccountsController

- Added Jbuilder gem for improved JSON response handling.
- Refactored index action in AccountsController to utilize Jbuilder for rendering JSON.
- Removed manual serialization of accounts and streamlined response structure.
- Implemented a before_action in BaseController to enforce JSON format for all API requests.

* Add transactions resource to API routes

- Added routes for transactions, allowing index, show, create, update, and destroy actions.
- This enhancement supports comprehensive transaction management within the API.

* Enhance API authentication and onboarding handling

- Updated BaseController to skip onboarding requirements for API endpoints and added manual token verification for OAuth authentication.
- Improved error handling and logging for invalid access tokens.
- Introduced a method to set up the current context for API requests, ensuring compatibility with session-like behavior.
- Excluded API paths from onboarding redirects in the Onboardable concern.
- Updated database schema to change resource_owner_id type from bigint to string for OAuth access grants.

* Fix rubocop offenses

- Fix indentation and spacing issues
- Convert single quotes to double quotes
- Add spaces inside array brackets
- Fix comment alignment
- Add missing trailing newlines
- Correct else/end alignment

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

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

* Fix API test failures and improve test reliability

- Fix ApiRateLimiterTest by removing mock users method and using fixtures
- Fix UsageControllerTest by removing mock users method and using fixtures
- Fix BaseControllerTest by using different users for multiple API keys
- Use unique display_key values with SecureRandom to avoid conflicts
- Fix double render issue in UsageController by returning after authorize_scope\!
- Specify controller name in routes for usage resource
- Remove trailing whitespace and empty lines per Rubocop

All tests now pass and linting is clean.

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

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

* Add API transactions controller warning to brakeman ignore

The account_id parameter in the API transactions controller is properly
validated on line 79: family.accounts.find(transaction_params[:account_id])
This ensures users can only create transactions in accounts belonging to
their family, making this a false positive.

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

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

---------

Signed-off-by: Josh Pigford <josh@joshpigford.com>
Co-authored-by: Claude <noreply@anthropic.com>

app/controllers/api/v1/usage_controller.rb

@@ -0,0 +1,38 @@
+class Api::V1::UsageController < Api::V1::BaseController
+  # GET /api/v1/usage
+  def show
+    return unless authorize_scope!(:read)
+
+    case @authentication_method
+    when :api_key
+      usage_info = @rate_limiter.usage_info
+      render_json({
+        api_key: {
+          name: @api_key.name,
+          scopes: @api_key.scopes,
+          last_used_at: @api_key.last_used_at,
+          created_at: @api_key.created_at
+        },
+        rate_limit: {
+          tier: usage_info[:tier],
+          limit: usage_info[:rate_limit],
+          current_count: usage_info[:current_count],
+          remaining: usage_info[:remaining],
+          reset_in_seconds: usage_info[:reset_time],
+          reset_at: Time.current + usage_info[:reset_time].seconds
+        }
+      })
+    when :oauth
+      # For OAuth, we don't track detailed usage yet, but we can return basic info
+      render_json({
+        authentication_method: "oauth",
+        message: "Detailed usage tracking is available for API key authentication"
+      })
+    else
+      render_json({
+        error: "invalid_authentication_method",
+        message: "Unable to determine usage information"
+      }, status: :bad_request)
+    end
+  end
+end