feat: add variable interpolation support for WebSocket requests (#6064)

* feat: add variable interpolation support for WebSocket requests

- Add WebSocket body interpolation in interpolateVars function
- Interpolate URL, headers, and all messages in request.body.ws array with full variable context
- Refactor sendWsRequest to use main process preparation (removes duplication)
- Add mode property to wsRequest object for proper request type detection
- Ensure consistent variable precedence matching HTTP/gRPC requests
- Centralize all interpolation logic in main process via prepareWsRequest

* Add Playwright tests for WebSocket variable interpolation

- Add tests for URL interpolation (wss://echo.{{url}}.org)
- Add tests for message content interpolation ({"test": "{{data}}"})
- Update test fixtures to use wss://echo.websocket.org echo server
- Add WEBSOCKET_FLOWS.md documentation
- Refactor queueWsMessage to handle variable interpolation in main process

* removed ws flow documentation

* chore: updated the network/index.js file to reduce merge conflicts by moving around code

* fix: added collection and item to WsQueryUrl Editor to fix available variable highlight

* chore: remove unnecessary whitespace in WebSocket event handlers

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Co-authored-by: Sid <siddharth@usebruno.com>

packages/bruno-app/src/components/RequestPane/WsQueryUrl/index.js

@@ -104,6 +104,8 @@ const WsQueryUrl = ({ item, collection, handleRun }) => {
             className="w-full"
             theme={displayedTheme}
             onRun={handleRun}
+            collection={collection}
+            item={item}
           />
           <div className="flex items-center h-full mr-2 cursor-pointer">
             <div