Added Query Params table with per-value copy support in Request Details

[dominicklee]

Description

This PR adds a structured Query Params table to the Request Details view, along with per-value copy functionality. This improvement directly aligns with the original author's desire of making the system perform similar to sites like Webhook.site

Problem

Currently, query parameters are only visible as part of the request Path (e.g. /callback?code=...&state=...), which makes them difficult to read and work with, especially for requests containing many parameters. For complex requests, developers would appreciate a clean way to extract the desired parameter value for testing.

This becomes particularly challenging in scenarios such as OAuth / OAuth2 REST API workflows (e.g. code, state, scope, error) or complex APIs that include multiple or repeated query parameters. Viewing or copying those parameters becomes tricky.

Long query strings reduce readability and increase friction when inspecting or copying individual values. The Webhook.site service typically parses and displays any query params as a table.

Solution

This PR introduces:

1. Structured Query Params Table
   Displays query parameters as key/value pairs
   Positioned in the Request Details view (before "Request body")
   Supports multiple values per key (preserves order using URLSearchParams.entries())

2. Per-Value Copy Button
   Adds a copy button next to each parameter value
   Uses existing Mantine CopyButton pattern for consistency
   Provides immediate visual feedback when copied

3. Improved Readability
   Monospace formatting for keys and values
   Handles empty values explicitly (renders as (empty))

Implementation Notes

• Implemented entirely in the frontend (request-details.tsx)
• Leverages existing request.url object and URLSearchParams
• No backend or API changes required
• Follows existing UI patterns and components (Mantine)

Checklist

• My code adheres to the style guidelines of this project
• I have conducted a self-review of my code
• I have added comments to my code, especially in areas that may be difficult to understand