feat(experiment): add experiments list page with filtering, pagination, and actions

[Zaimwa9]

Thanks for submitting a PR! Please check the boxes below:

• I have read the Contributing Guide.
• I have added information to docs/ if required so people know about the feature.
• I have filled in the "Changes" section below.
• I have filled in the "How did you test this code" section below.

Changes

• Added ExperimentsListControls — tab filter (All / Running / Draft / Paused / Completed) with status_counts and search bar
• Added ExperimentsTable — name, linked flag, status badge, variation count, last updated, actions dropdown
• Added StatusBadge — coloured pill per experiment status
• Added ExperimentActionDropdown — Start / Pause / Complete / Delete with confirmation modals
• Added RTK Query mutations: start, pause, complete, delete (all invalidate list tag)
• Upgraded useGetExperimentsQuery to support page, page_size, status, q with transformCorePaging
• Widened Experiment.feature from number to ExperimentFeature (full object); typed ExperimentFeature.type as FeatureType
• Added ExperimentStatusCounts and status_counts to paginated response type
• Deduplicated status labels into experiments/constants.ts
• All new components follow ComponentName/{tsx,scss,index.ts} folder structure
• Migrated Experiment Name field to <InputGroup> (finishing feat(experimentation): add experiment creation wizard frontend #7596 cleanup)
• Fixed useMemo → useCallback, NaN-safe reduce on status_counts, Paging hidden when empty
• Updated ui-patterns.md: corrected Tabs path, documented destructive on openConfirm

How did you test this code?

• Manual testing via ENV=local npm run dev
• Verified list rendering, status tab filtering with counts, search, pagination
• Verified lifecycle actions (Start / Pause / Complete / Delete) with confirmation modals
• Verified all three empty states (no warehouse, no experiments, no filter match)
• tsc --noEmit and eslint pass on all touched files

[Zaimwa9]

@gemini-code-assist review

[gemini-code-assist]

Code Review

This pull request updates the UI patterns documentation and introduces comprehensive pagination, filtering, and action controls for the experiments list, including new endpoints for starting, pausing, completing, and deleting experiments. The review feedback highlights several critical issues that will cause compilation errors or runtime crashes, such as missing imports across multiple files, incorrect event typing, missing closeModal calls in confirmation dialogs, and unsafe property access on potentially nullable feature objects.

[talissoncosta]

left some suggestions, thanks for handling that @Zaimwa9

[talissoncosta]

Just some small points...

Can you please check the experiment form?

The input is wider and the labels are not following the same pattern as the others.

Also here on metrics..

I might have missed on the previous pr