feat(experiments): attach a primary metric in the create experiment wizard

[Zaimwa9]

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• 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

Wires up the Measurement step of the Create Experiment wizard so a primary metric can be attached when creating an experiment.

• Select one existing metric (paginated list of 5 + search), or create a new metric inline via a centred modal without leaving the wizard.
• Pick the expected direction, prefilled from the metric's own direction.
• The metric is required to launch; it's sent inline in the create payload (backend support landed in feat(experimentation): accept inline metrics on experiment creation #7770).
• Review step summarises the attached metric and chosen direction, and the experiments list shows the attached primary metric.

How did you test this code?

Manually, against a local API + warehouse:

1. Open Experiments → Create experiment, complete Setup.
2. On Measurement, search/select a metric (add >5 to see paging), confirm the Primary badge and direction prefill.
3. Use Create Metric to add one inline; confirm it auto-selects.
4. Launch and verify the experiment is created with the metric attached, and that it appears in the experiments list's Primary Metric column.
5. Confirm launch is blocked until a metric + direction are chosen.

Plus npm run typecheck and eslint on the touched files.

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Project	Deployment	Actions	Updated (UTC)
docs	Ready	Preview, Comment	Jun 16, 2026 6:36am
flagsmith-frontend-preview	Ready	Preview, Comment	Jun 16, 2026 6:36am
flagsmith-frontend-staging	Ready	Preview, Comment	Jun 16, 2026 6:36am

[github-actions]

Docker builds report

Image	Build Status	Security report
ghcr.io/flagsmith/flagsmith-api-test:pr-7780	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-e2e:pr-7780	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-api:pr-7780	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith:pr-7780	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-private-cloud:pr-7780	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-frontend:pr-7780	Finished ✅	Results ✅

[github-actions]

Playwright Test Results (oss - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 33.1 seconds
 483b171
 🔄 Run: #17490 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-arm-16)

 19 passed

Details

 19 tests across 15 suites
 1 minute, 9 seconds
 483b171
 🔄 Run: #17490 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-arm-16)

 1 passed

Details

 1 test across 1 suite
 44.1 seconds
 483b171
 🔄 Run: #17490 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 55.1 seconds
 483b171
 🔄 Run: #17490 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 32.9 seconds
 ccdbdd3
 🔄 Run: #17493 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-arm-16)

 1 passed

Details

 1 test across 1 suite
 44.1 seconds
 ccdbdd3
 🔄 Run: #17493 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-arm-16)

 2 passed

Details

 2 tests across 2 suites
 1 minute, 13 seconds
 ccdbdd3
 🔄 Run: #17493 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 54.7 seconds
 ccdbdd3
 🔄 Run: #17493 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 32.9 seconds
 1a41e93
 🔄 Run: #17495 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-arm-16)

 1 passed

Details

 1 test across 1 suite
 45.1 seconds
 1a41e93
 🔄 Run: #17495 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-16)

 2 passed

Details

 2 tests across 2 suites
 45.7 seconds
 1a41e93
 🔄 Run: #17495 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-arm-16)

 2 passed

Details

 2 tests across 2 suites
 43.5 seconds
 1a41e93
 🔄 Run: #17495 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 33.9 seconds
 0a4b592
 🔄 Run: #17497 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-arm-16)

 1 passed

Details

 1 test across 1 suite
 43.1 seconds
 0a4b592
 🔄 Run: #17497 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-16)

 3 passed

Details

 3 tests across 3 suites
 35.6 seconds
 0a4b592
 🔄 Run: #17497 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-arm-16)

 2 passed

Details

 2 tests across 2 suites
 1 minute, 8 seconds
 0a4b592
 🔄 Run: #17497 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-16)

 1 passed

Details

 1 test across 1 suite
 33 seconds
 99100fa
 🔄 Run: #17525 (attempt 1)

Playwright Test Results (oss - depot-ubuntu-latest-arm-16)

 1 passed

Details

 1 test across 1 suite
 43.1 seconds
 99100fa
 🔄 Run: #17525 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-arm-16)

 1 passed

Details

 1 test across 1 suite
 39.5 seconds
 99100fa
 🔄 Run: #17525 (attempt 1)

Playwright Test Results (private-cloud - depot-ubuntu-latest-16)

 3 passed

Details

 3 tests across 3 suites
 33.7 seconds
 99100fa
 🔄 Run: #17525 (attempt 1)

[github-actions]

Visual Regression

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[Zaimwa9]

@gemini-code-assist review

[gemini-code-assist]

Code Review

This pull request introduces a new CenteredModal component, enhances SelectableCard and ContentCard with additional layout options, and integrates a measurement step into the experiment creation wizard to allow selecting a primary metric and its expected direction. It also optimizes warehouse connection queries by adding an option to exclude event stats and prevents selecting feature flags already associated with active experiments. The review feedback highlights critical issues, including a mismatch in cache keys during pessimistic updates, a loading state (isEnabling) that gets stuck on successful warehouse connection creation, a hardcoded page size limit of 100 when checking for active experiments, and a potential runtime crash due to a missing defensive check on experiment.feature.

[Zaimwa9]

@gemini-code-assist review

[gemini-code-assist]

Code Review

This pull request introduces the ability to select a primary metric and define its expected direction during the experiment creation wizard. It also adds a reusable CenteredModal component, updates UI cards (SelectableCard and ContentCard) to support tags and descriptions, and prevents users from selecting feature flags that are already associated with active experiments. The review feedback highlights three key issues: the need to validate the final Review step in the wizard to disable the launch button when previous steps are invalid, fixing a state desynchronization issue when clearing the expected direction dropdown, and increasing the hardcoded page size when querying existing experiments to avoid missing active flags.