Forms: Update dashboard styling for consistency

[lezama]

This PR updates the Jetpack Forms dashboard styling to improve visual consistency across the interface.

Before

After

Header & Typography:

• Created custom Header component with standardized title sizing (15px)
• Reduced header padding from 16px to 8px vertical
• Added proper subtitle spacing (8px bottom padding, removed margin)
• Fixed vertical gaps by setting VStack spacing to 0

Buttons:

• Changed all CTA buttons from __next40pxDefaultSize to size="compact" for consistency
• Updated: CreateFormButton, IntegrationsButton, ExportResponsesButton, EmptyTrashButton, EmptySpamButton

Tabs:

• Adjusted tabs padding to match header (20px horizontal)
• Replaced custom count span with Badge component from @automattic/ui
• Added flex layout with 4px gap for proper label-badge spacing

Colors:

• Applied variables consistently throughout

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

N/A - This is a styling-only change that improves visual consistency without functional changes.

Does this pull request change what data or activity we track or use?

No.

Testing instructions:

• Go to Jetpack Forms dashboard in wp-admin
• Verify the header has more compact padding (should feel less spacious)
• Check that all action buttons (Create form, Integrations, Export, Empty trash/spam) have consistent compact sizing
• Navigate between Inbox/Spam/Trash tabs and verify the count badges display correctly with proper spacing between label and number
• Check both desktop and mobile viewports to ensure responsive styling works correctly

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack), and enable the update/forms-styling-consistency branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack update/forms-styling-consistency

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• 🔴 Add a "[Status]" label (In Progress, Needs Review, ...).
  
• 🔴 Add a "[Type]" label (Bug, Enhancement, Janitorial, Task).
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

Follow this PR Review Process:

1. Ensure all required checks appearing at the bottom of this PR are passing.
2. Make sure to test your changes on all platforms that it applies to. You're responsible for the quality of the code you ship.
3. You can use GitHub's Reviewers functionality to request a review.
4. When it's reviewed and merged, you will be pinged in Slack to deploy the changes to WordPress.com simple once the build is done.

If you have questions about anything, reach out in #jetpack-developers for guidance!

[jp-launch-control]

Code Coverage Summary

1 file is newly checked for coverage.

File	Coverage
projects/packages/forms/src/dashboard/components/layout/header.tsx	0/1 (0.00%) 💔

Full summary · PHP report · JS report

_{If appropriate, add one of these labels to override the failing coverage check: Covered by non-unit tests Use to ignore the Code coverage requirement check when E2Es or other non-unit tests cover the code Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR I don't care about code coverage for this PR Use this label to ignore the check for insufficient code coveage.}