fix(jetbrains): prefer dataDirectoryName for plugin path

[peckfly]

Summary

• prefer dataDirectoryName from product-info.json when resolving JetBrains plugin directories
• keep the existing product/build-based path derivation as a fallback
• add tests covering both the preferred and fallback behaviors

Why

Some JetBrains IDEs use a data directory name that does not match the path derived from productCode + buildNumber. In those cases, the plugin can be installed into the wrong directory.

Testing

• cargo test mdm::jetbrains::detection::tests:: -- --nocapture
• cargo fmt -- --check

[CLAassistant]

All committers have signed the CLA.

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 2 additional findings.

[svarlamov]

Thanks for the contribution @peckfly! What behavior/bug is this fixing?

[peckfly]

Thanks for the contribution @peckfly! What behavior/bug is this fixing?

This fixes JetBrains plugin installation/detection on IDEs where the actual config/plugins directory is defined by dataDirectoryName in product-info.json, but the current code derives the directory from productCode + buildNumber.

For example, on IntelliJ IDEA 2026.1, product-info.json reports dataDirectoryName=IntelliJIdea2026.1, while the current logic derives IU2026.1. That causes git-ai to look in / install into the wrong plugins directory, so the plugin may appear missing or not get loaded by the IDE.

This change prefers dataDirectoryName when available, and falls back to the existing productCode + buildNumber behavior otherwise.

[svarlamov]

Great context, thank you for the contribution! Looking forward to more! 🙏