system/nxstore: Add LVGL touchscreen app-store frontend.

[aviralgarg05]

Summary

Add a small LVGL front end for browsing and managing nxpkg entries. NXStore
uses the public <system/nxpkg.h> API and keeps slow work off the UI thread.

NXStore supervises each launched application. Closing an app sends SIGTERM;
the package list returns after the child exits.

Impact

• New feature: a graphical package front end
• Build: enabled through Kconfig; requires LVGL, nxpkg, cJSON, and waitpid
• Hardware: requires a framebuffer and touchscreen
• Documentation: Documentation: Update nxpkg and add nxstore guide. nuttx#18875
• Compatibility: the nxpkg command-line interface is unchanged

Testing

Host: macOS 26.5, arm64, xtensa-esp-elf-gcc 14.2.0.
Target: Waveshare ESP32-S3-Touch-LCD-7 with an 800x480 RGB565 display and
GT911 touchscreen.

• nxstyle, tools/checkpatch.sh, codespell, and git diff --check
• built NXStore and nxpkg against current master
• installed and launched a package on hardware
• closed it through the supervisor bar and confirmed the updated list returned

PR verification Self-Check

• This PR introduces one focused change.
• I have updated all required description fields above.
• I have reviewed and signed every commit.
• This PR adheres to the current contribution and coding guidelines.
• My PR is still work in progress.
• My PR is ready for review and can be safely merged.

[acassis]

@aviralgarg05 nice work, please include a scheenshot in the Testing. Also please add a companion nuttx/Documentation

[aviralgarg05]

Thanks. I have added a photograph of NXStore running on the ESP32-S3 target to the Testing section. The companion documentation is in apache/nuttx#18875, and the later signed-tree build and serial evidence remain recorded in the PR description.

[acassis]

Thanks. I have added a photograph of NXStore running on the ESP32-S3 target to the Testing section. The companion documentation is in apache/nuttx#18875, and the later signed-tree build and serial evidence remain recorded in the PR description.

@aviralgarg05 please double check, there is not screenshot in apache/nuttx#18875

[aviralgarg05]

@aviralgarg05 please double check, there is not screenshot in apache/nuttx#18875

Sorry, missed it, Done now

[acassis]

@aviralgarg05 please double check, there is not screenshot in apache/nuttx#18875

Sorry, missed it, Done now

don't worry

[github-actions]

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

• system/nxpkg: Complete the package lifecycle and command line. #3720 @ 51b68e8

CI run: https://github.com/apache/nuttx-apps/actions/runs/31816523839

[linguini1]

Honestly not going to finish reviewing this unless more effort is put into these patches to review AI output. These comments are way too long, some of the ones submitted before have been unrelated, and this is a consistent issue.

[linguini1]

On the board: the catalog was listed, a package was installed and launched by tapping it, closing it sent SIGTERM and the application exited on its
own, and the list came back with the package now shown as installed.

Show this. Text description is not enough.

[aviralgarg05]

Show this. Text description is not enough.

Will record a video of it, and put up asap

[github-actions]

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

• system/nxpkg: Complete the package lifecycle and command line. #3720 @ 0d01415

CI run: https://github.com/apache/nuttx-apps/actions/runs/31879473762

[linguini1]

Even just photos is fine

[xiaoxiang781216]

@aviralgarg05 squash you change into one patch.

[aviralgarg05]

@linguini1

IMG_0787-github.1.mp4

The video shows catalog -> install and launch -> cooperative Close -> updated installed catalog
The evidence is a plain black screen just for reference to show the working of flow

[github-actions]

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

• system/nxpkg: Complete the package lifecycle and command line. #3720 @ 6fa06f0

CI run: https://github.com/apache/nuttx-apps/actions/runs/31955926952

[cederom]

Thank you @aviralgarg05 very nice idea, documentation is welcome :-)