This commit adds a new file `TriggerStyle.cs` which contains the `TriggerStyle` enum. The enum defines three trigger styles for events in an HTMX response.

In addition, this commit modifies the `HtmxResponse.cs` file to include several new methods:
- `Location(string url)`: Sets the location header for client-side redirect.
- `PushUrl(string url)`: Pushes a new URL onto the history stack.
- `Redirect(string url)`: Sets the redirect header for client-side redirect.
- `Refresh()`: Enables a client-side full refresh of the page.
- `ReplaceUrl(string url)`: Replaces the current URL in the location bar.
- `Reswap(SwapStyle swapStyle)`: Allows specifying how the response will be swapped.
- `Retarget(string selector)`: Updates the target of content update to a different element on the page.
- `Reselect(string selector)`: Allows choosing which part of the response is used to be swapped in.
- `Trigger(string eventName, object? detail = null, TriggerStyle timing = TriggerStyle.Default)`: Triggers client-side events with optional event details and timing.

These changes enhance functionality related to handling HTMX responses.

Switch from HashSet to retain event ordering

The code changes in this commit switch from using a HashSet to using a List in order to retain the ordering of events. This change ensures that the events are stored and outputted in the same order they were added, which is important for maintaining consistency. Additionally, a boolean variable "exists" is introduced to check if an event already exists before adding it to the list.

This commit adds the HtmxResponse class implementation, which is responsible for handling HTTP responses in the Htmxor library. It includes methods for adding various response headers such as Location, PushUrl, Redirect, Refresh, ReplaceUrl, Reswap, Retarget, Reselect, and Trigger.

The commit also includes unit tests for each of these methods to ensure their functionality. The tests cover scenarios such as adding different headers with different values and checking if the headers are correctly set in the response.

Additionally, a MockHeaderDictionary class is added to provide a mock implementation of the IHeaderDictionary interface for testing purposes. This allows us to simulate HTTP headers in our unit tests without relying on actual HTTP requests or responses.

Overall, this commit introduces the necessary code changes to support Htmx response handling and provides comprehensive test coverage for this functionality.

- Change access modifiers from internal to public in `MockHeaderDictionary`, `MockHttpContext`, `MockHttpRequest`, `MockHttpResponse`, and `MockResponseCookies` classes.

…ents

- Make _serializerOptions field static for improved performance and memory usage.

…etail into the result

This commit modifies the `MergeTrigger` method in the `HtmxResponse` class. It introduces changes to aggregate existing headers and merge events with details into the result. The code now uses a `StringBuilder` to build the JSON representation of aggregated properties across all header values for a given header key. Duplicate keys are not removed for performance reasons, as the produced JSON is still valid. This approach does not validate any syntax of existing headers as a performance consideration.