fix(variables): correct scripted-variable persistence races and cross-request propagation (#8406)

* feat(collections): implement sliding window for script request UIDs to manage stale updates

- Introduced a bounded sliding window mechanism for tracking recent script request UIDs, allowing for better handling of stale updates from superseded or cancelled requests.
- Updated relevant functions to utilize the new `isStaleScriptRequest` utility for improved clarity and maintainability.
- Enhanced the persistence logic to ensure that updates from retired requests do not interfere with newer requests, improving data integrity during concurrent operations.
- Added comprehensive tests to validate the behavior of the new UID management system and its impact on variable propagation across requests.

* refactor(tests): remove outdated test for persistentEnvVariables in runtime tests

- Eliminated the test case that checked for the inclusion of persistentEnvVariables in the result, as it is no longer relevant.
- Cleaned up the test suite to enhance clarity and maintainability, focusing on relevant assertions for variable management.

* refactor(collections): simplify environment persistence logic and remove stale request handling

- Updated the `persistActiveEnvironment` and related functions to eliminate the requestUid parameter, streamlining the logic for environment persistence.
- Removed outdated checks for stale updates from superseded requests, enhancing clarity and maintainability.
- Deleted the `_scriptRequestUids` management code and associated tests, as they are no longer necessary for the current implementation.
- Improved the handling of environment updates to ensure accurate state management without stale data interference.

* refactor(filesystem): remove unused hasJsExtension function

- Deleted the `hasJsExtension` utility function from the filesystem module as it was no longer needed.
- Cleaned up the exports to enhance clarity and maintainability of the codebase.

* test(network): add unit tests for applyCollectionVarsToCollectionRoot

* refactor(ipc, environments): implement file locking for environment updates

- Updated the environment persistence logic in both `collection.js` and `workspace-environments.js` to utilize file locking during read and write operations.
- This change ensures that concurrent access to environment files is managed safely, preventing potential data corruption and enhancing reliability during updates.

tests/scripting/bru-api/collection-var-multi-request/collection-var-multi-request.spec.ts

@@ -0,0 +1,24 @@
+import { test } from '../../../../playwright';
+import { openCollection, selectEnvironment } from '../../../utils/page';
+import { runCollection, validateRunnerResults } from '../../../utils/page/runner';
+
+test.describe('Script collection-variable propagation across requests in one runner invocation', () => {
+  test('request 2 observes request 1\'s setCollectionVar write', async ({
+    pageWithUserData: page
+  }) => {
+    await openCollection(page, 'collection-var-multi-request-test');
+    await selectEnvironment(page, 'Test');
+    await runCollection(page, 'collection-var-multi-request-test');
+
+    // Both requests should pass: req-1 sets counter="1"; req-2 reads counter
+    // (must see "1"), records it in seenInReq2, then sets counter="2".
+    // If applyCollectionVarsToCollectionRoot didn't propagate the change to
+    // collection.root.request.vars.req, req-2's mergeVars would rebuild
+    // collectionVariables from the pre-run "0" and req-2's first test would fail.
+    await validateRunnerResults(page, {
+      totalRequests: 2,
+      passed: 2,
+      failed: 0
+    });
+  });
+});

tests/scripting/bru-api/collection-var-multi-request/fixtures/collections/collection-var-multi-request-test/bruno.json

@@ -0,0 +1,9 @@
+{
+  "version": "1",
+  "name": "collection-var-multi-request-test",
+  "type": "collection",
+  "ignore": [
+    "node_modules",
+    ".git"
+  ]
+}

tests/scripting/bru-api/collection-var-multi-request/fixtures/collections/collection-var-multi-request-test/collection.bru

@@ -0,0 +1,7 @@
+meta {
+  name: collection
+}
+
+vars:pre-request {
+  counter: 0
+}

tests/scripting/bru-api/collection-var-multi-request/fixtures/collections/collection-var-multi-request-test/environments/Test.bru

@@ -0,0 +1,3 @@
+vars {
+  host: https://testbench-sanity.usebruno.com
+}

tests/scripting/bru-api/collection-var-multi-request/fixtures/collections/collection-var-multi-request-test/req-1-write.bru

@@ -0,0 +1,21 @@
+meta {
+  name: req-1-write
+  type: http
+  seq: 1
+}
+
+get {
+  url: {{host}}/ping
+  body: none
+  auth: none
+}
+
+script:post-response {
+  bru.setCollectionVar("counter", "1");
+}
+
+tests {
+  test("request 1 wrote counter=1", function() {
+    expect(bru.getCollectionVar("counter")).to.equal("1");
+  });
+}

tests/scripting/bru-api/collection-var-multi-request/fixtures/collections/collection-var-multi-request-test/req-2-read-and-write.bru

@@ -0,0 +1,31 @@
+meta {
+  name: req-2-read-and-write
+  type: http
+  seq: 2
+}
+
+get {
+  url: {{host}}/ping
+  body: none
+  auth: none
+}
+
+script:post-response {
+  // Request 2 must observe request 1's setCollectionVar write. The electron-side
+  // applyCollectionVarsToCollectionRoot in sendVariableUpdates is what makes this
+  // visible — without it, mergeVars rebuilds request 2's collectionVariables from
+  // the original collection.root and req-2's read returns "0".
+  const prev = bru.getCollectionVar("counter");
+  bru.setCollectionVar("seenInReq2", prev);
+  bru.setCollectionVar("counter", "2");
+}
+
+tests {
+  test("request 2 observed request 1's collection-var write", function() {
+    expect(bru.getCollectionVar("seenInReq2")).to.equal("1");
+  });
+
+  test("request 2 wrote counter=2", function() {
+    expect(bru.getCollectionVar("counter")).to.equal("2");
+  });
+}

tests/scripting/bru-api/collection-var-multi-request/init-user-data/collection-security.json

@@ -0,0 +1,10 @@
+{
+  "collections": [
+    {
+      "path": "{{collectionPath}}/collection-var-multi-request-test",
+      "securityConfig": {
+        "jsSandboxMode": "developer"
+      }
+    }
+  ]
+}

tests/scripting/bru-api/collection-var-multi-request/init-user-data/preferences.json

@@ -0,0 +1,5 @@
+{
+  "lastOpenedCollections": [
+    "{{collectionPath}}/collection-var-multi-request-test"
+  ]
+}