docs: clarify local plugin install target and clone options

Author: shuofengzhang

CONTRIBUTING.md

@@ -16,7 +16,7 @@ Before merging, test your changes locally:
 
    ```bash
    claude plugin marketplace add ~/path/to/sentry-skills
-   claude plugin install sentry-skills
+   claude plugin install sentry-skills@sentry-skills
    ```
 
 2. **Restart Claude Code** to pick up changes

README.md

@@ -73,9 +73,13 @@ Works with Claude Code, Cursor, Cline, GitHub Copilot, and other compatible agen
 ### Local Development
 
 ```bash
+# SSH
 git clone git@github.com:getsentry/skills.git ~/sentry-skills
+# or HTTPS
+git clone https://github.com/getsentry/skills.git ~/sentry-skills
+
 claude plugin marketplace add ~/sentry-skills
-claude plugin install sentry-skills
+claude plugin install sentry-skills@sentry-skills
 ```
 
 ### Repository Structure