feat: add category filtering and tagging for abilities in Ability Table

[HILAYTRIVEDI]

What?

Closes #344

Adds a Category filter to the Abilities Explorer, allowing users to filter abilities by functional area (e.g., Image, Editorial, Content).

Why?

The Abilities Explorer currently only allows filtering by Provider (Core, Plugin, Theme), which makes it difficult to find abilities based on what they do, especially in large lists. This PR addresses the need for functional filtering by introducing a Category filter, making it easier to discover abilities by their purpose (e.g., image handling, content editing).
References: [Original issue] (summarize: lack of functional filtering in Abilities Explorer).

How?

This PR adds a Category filter dropdown to the Abilities Explorer UI. Categories are auto-derived from ability slugs using keyword matching, and can be extended or overridden by third-party plugins via the ai_ability_category_map and ai_ability_tags filter hooks. The filter works identically to the Provider dropdown: it is server-side, persists in the URL, and is submitted via the same Filter button.

Testing Instructions

1. Go to the Abilities Explorer in the admin interface.
2. Observe the new Category filter dropdown next to the Provider filter.
3. Select a category (e.g., Image, Editorial, Content) and click the Filter button.
4. Confirm that the list of abilities updates to show only those matching the selected category.
5. Change the Provider filter and verify that both filters work together as expected.
6. Check that the selected filters persist in the URL and after page reload.

Testing Instructions for Keyboard

1. Tab to the Category filter dropdown.
2. Use arrow keys to navigate and select a category.
3. Tab to the Filter button and press Enter.
4. Verify that the filtered results are accessible and that focus order is logical.
5. Tab through the Provider filter and ensure all controls are reachable and operable via keyboard.

Screenshots or screencast

https://www.awesomescreenshot.com/video/50968973?key=5acd67e6e7dc53b4aa9d85fe075a9709

[github-actions]

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Co-authored-by: dkotter <dkotter@git.wordpress.org>

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[codecov]

Codecov Report

❌ Patch coverage is 84.37500% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.95%. Comparing base (d479cf3) to head (0126bf0).
⚠️ Report is 13 commits behind head on develop.

Files with missing lines	Patch %	Lines
...s/Experiments/Abilities_Explorer/Ability_Table.php	77.27%	5 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop     #355      +/-   ##
=============================================
+ Coverage      57.70%   57.95%   +0.25%     
- Complexity       617      629      +12     
=============================================
  Files             46       46              
  Lines           3173     3204      +31     
=============================================
+ Hits            1831     1857      +26     
- Misses          1342     1347       +5     

Flag	Coverage Δ
unit	57.95% <84.37%> (+0.25%)	⬆️

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[dkotter]

Would also be great to add some E2E tests to cover the changes here, verifying the category dropdown renders and works as expected

[HILAYTRIVEDI]

Would also be great to add some E2E tests to cover the changes here, verifying the category dropdown renders and works as expected

@dkotter I added the E2E test for the category dropdown.

[dkotter]

Sorry for all the back and forth here, this is looking really good and I think we're close, just a few final things I've noticed.

[HILAYTRIVEDI]

Sorry for all the back and forth here, this is looking really good and I think we're close, just a few final things I've noticed.

@dkotter no worries at all . I am new to the AI contribution in core WordPress. So I am actually grateful for your time you are giving in review and feedback. I really appreciate it . As moving forward in other PRs I will keep this feedbacks in mind before review. 🙇