feat: add JavaScript/JSX asset handler

[aabhinavvvvvvv]

Summary

Adds a JavaScriptHandler to detect libraries, inputs, and outputs in JavaScript files, closing #362.

Files changed:

• app/services/assets/handlers/javascript.js — new handler supporting .js, .jsx, .mjs, .cjs files
• app/constants/assets-config.js — registers JavaScript extensions
• app/preload.js — instantiates JavaScriptHandler
• app/utils/workflow.js — registers handler in getAssetType, getAllDependencies, getLibraryDependencies
• app/images/js.svg — JavaScript icon for the dependency graph
• app/components/Workflow/DependencyGraph/CustomNodes/Code/CodeNode.js — icon entry for JS nodes
• app/components/Workflow/DependencyGraph/DependencyGraphEChart.js — icon entry for JS nodes
• docs/Assets.md — documents what the handler detects
• test/services/assets/handlers/javascript.spec.js — 20 unit tests for the handler
• test/services/assets/asset.spec.js — extension detection tests
• test/utils/workflow.spec.js — dependency and asset type tests

Detection coverage:

Category	Patterns
Libraries	ES module imports (import x from 'y', named, namespace, side-effect) and CommonJS require('y')
Inputs	fs.readFileSync, fs.readFile, fs.createReadStream
Outputs	fs.writeFileSync, fs.writeFile, fs.appendFile, fs.appendFileSync, fs.createWriteStream

[lrasmus]

The code looks good - I have a few requests for additional unit tests. The code appears to handle these scenarios, I just want to ensure we have test cases to show they work.

[lrasmus]

Wonderful job with all the new added tests - it uncovered something I hadn't detected in code review. Please see the note about one of the tests currently failing, and let me know if you're seeing something different on your end.

[aabhinavvvvvvv]

the require regex was missing the ^[^/]*? guard that the import regexes had. Fixed that, and also corrected the Windows path test to use single backslashes. All 31 tests passing now.

[lrasmus]

Perfect, thank you SO much for this implementation, and for the quick changes on the unit tests!