Add Launchy to third-party Run plugins (#49080)

## Summary of the Pull Request

Adds Launchy to the third-party PowerToys Run plugins list.

Launchy is a community PowerToys Run plugin that indexes and launches
files from user-configured folders with per-folder extension, recursion
depth, and folder inclusion rules.

## PR Checklist

- [ ] Closes: #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [x] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

## Detailed Description of the Pull Request / Additional comments

This updates the existing third-party PowerToys Run plugins list with a
link to the Launchy plugin repository.

No product code is changed.

## Validation Steps Performed

- Verified the Launchy repository is public.
- Verified the plugin README includes installation, usage, settings,
screenshots, and release assets.
- Verified this PR only changes doc/thirdPartyRunPlugins.md.

---------

Co-authored-by: PsychodelEKS <konstantin.efremov@clickio.com>

doc/thirdPartyRunPlugins.md

@@ -54,6 +54,7 @@ Contact the developers of a plugin directly for assistance with a specific plugi
 | [Project Launcher Plugin](https://github.com/artickc/ProjectLauncherPowerToysPlugin) | [artickc](https://github.com/artickc) | Access your projects using Project Launcher and PowerToys Run |
 | [CheatSheets](https://github.com/ruslanlap/PowerToysRun-CheatSheets) | [ruslanlap](https://github.com/ruslanlap) | 📚 Find cheat sheets and command examples instantly from tldr pages, cheat.sh, and devhints.io. Features include favorites system, categories, offline mode, and smart caching. |
 | [QuickAI](https://github.com/ruslanlap/PowerToysRun-QuickAi) | [ruslanlap](https://github.com/ruslanlap) | AI-powered assistance with instant, smart responses from multiple providers (Groq, Together, Fireworks, OpenRouter, Cohere) |
+| [Launchy](https://github.com/PsychodelEKS/PowerToysRun-Launchy) | [PsychodelEKS](https://github.com/PsychodelEKS) | Index and launch files from configured folders |
 
 ## Extending software plugins