fix: add pm-integration-features-group classes for theme compatibility

Category integrations block now uses pm-integration-features-group class
so site theme styles (like .integration-content .pm-integration-features-group)
apply correctly for borders, backgrounds, and other styling.

Changes:
- Added pm-integration-features-group and has-features classes to wrapper
- Added pm-integration-features-group__header class to header
- Added pm-integration-features-group__features class to features container

0.4.3 - Revert shared styles, standalone styles per block

fix: match category-integrations styling to integration-features-group

- Remove arrow indicators from links
- Simplify link colors to inherit from site theme
- Adjust spacing and borders to match existing patterns
- Bump version to 0.4.1

chore: release v0.4.0

v0.4.2 - Match category-integrations styling to integration-features-…

…group

fix: rename repo to integration-features for Git Updater compatibility

- Repo slug now matches plugin folder and text domain
- Asset naming now correct: integration-features-*.zip

fix: correct release asset naming for Git Updater

Asset must be named $repo-*.zip (integration-features-block-*.zip)
per Git Updater requirements

fix: use full URL for GitHub Plugin URI

Git Updater requires full URL format for proper package resolution

fix: release workflow for Git Updater compatibility

- Change tag pattern from v* to semver without prefix
- Git Updater requires tags like 0.3.1, not v0.3.1
- Bump version to 0.3.1

chore: Add package-lock.json for CI (npm ci requires it)