fix: plugin root

[swatDong]

To fix the skill install issue (#363)

The plugin root/source was changed in (#148) and (#223), then has duplicated prefix ./.github/plugins, thus the skills command failed to detect those skills under plugins.
This PR changes to "pluginRoot": "./" , which keeps pluginRoot for compatibility and uses ./ as no-op.

[Copilot]

Pull request overview

This PR fixes a skill-installation bug (issue #363) caused by a duplicated path prefix in the npx skills marketplace manifest. Previously, pluginRoot was ./.github/plugins while every plugin source entry already contained the full ./.github/plugins/... path, so the two were joined into a duplicated, non-existent path and plugin skills could not be detected. The change sets pluginRoot to ./, making it an effective no-op that leaves the already-complete source paths to resolve correctly from the repository root. This is functionally consistent with the sibling manifest .github/plugin/marketplace.json, which has no pluginRoot and also uses full source paths.

Changes:

• Change pluginRoot in .claude-plugin/marketplace.json from ./.github/plugins to ./ to eliminate the duplicated path prefix.

[JasonYeMSFT]

@swatDong I don't think this is the right fix for the problem. The edited file is for plugins referenced by this marketplace. These plugins agreed to set their plugin root to .github/plugins. If you change it, all the plugins that depend on this will break. skills.sh doesn't respect the plugin spec and doesn't discover skills through referenced plugins. For your skill, people have two alternative methods to install the skill

1. Use the marketplace/plugin feature to install the azure plugin. Since microsoft-foundry is a part of azure plugin, installing azure plugin will install microsoft-foundry skill.
2. Use skills.sh but in the cmd options set the repo to microsoft/azure-skills. That repo has the plugin files.

@thegovind FYI.

[swatDong]

@swatDong I don't think this is the right fix for the problem. The edited file is for plugins referenced by this marketplace. These plugins agreed to set their plugin root to .github/plugins. If you change it, all the plugins that depend on this will break. skills.sh doesn't respect the plugin spec and doesn't discover skills through referenced plugins. For your skill, people have two alternative methods to install the skill

1. Use the marketplace/plugin feature to install the azure plugin. Since microsoft-foundry is a part of azure plugin, installing azure plugin will install microsoft-foundry skill.
2. Use skills.sh but in the cmd options set the repo to microsoft/azure-skills. That repo has the plugin files.

@thegovind FYI.

I met this issue on testing microsoft-foundry skill, but actually it occurs on ALL plugin skills, azure-sdk-*, azure-skills, deep-wiki, ...
So for users who starts from https://microsoft.github.io/skills/ or this repo's README, the npx skills add command fails on all those skills.