Added gift subscriptions discovery section in membership settings

[minimaluminium]

ref https://linear.app/ghost/issue/BER-3676/add-gift-subscriptions-discovery-link-in-settings

Mirrors the tips & donations pattern with a shareable link and preview/copy controls. Gated on the giftSubscriptions flag and Stripe being connected.

[coderabbitai]

Walkthrough

This PR introduces gift subscriptions support to the admin settings. A new GiftSubscriptions component displays a shareable URL derived from the site URL with Preview and Copy actions. The component is integrated into Membership settings with search keywords and a feature flag check that requires both the giftSubscriptions flag and Stripe to be enabled. A corresponding navigation item and search keywords are added to the Sidebar, also gated by the same feature flag and Stripe availability conditions.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding a gift subscriptions discovery section in membership settings, matching the changeset's primary objective.
Description check	✅ Passed	The description is directly related to the changeset, explaining the implementation pattern (mirrors tips & donations), key features (shareable link, preview/copy controls), and gating conditions (feature flag and Stripe requirement).
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch gift-subscriptions/discovery-link

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In
`@apps/admin-x-settings/src/components/settings/membership/gift-subscriptions.tsx`:
- Line 10: The current giftUrl construction uses siteData?.url directly and can
produce "undefined/..." if siteData or siteData.url is missing; update the logic
around giftUrl (the giftUrl constant) to defensively handle missing siteData by
either returning early from the component when siteData?.url is falsy or by
computing a safe baseUrl (e.g., const base = siteData?.url ?
siteData.url.replace(/\/$/, '') : window.location?.origin || '') and then
building giftUrl from that base; ensure you reference the giftUrl constant and
any early-return placement inside the component so copy/preview are disabled or
hidden when valid siteData is unavailable.
- Around line 12-16: The copyGiftUrl function should handle clipboard failures
and clear the timeout on unmount: make writeText usage async and wrap it in
try/catch (call navigator.clipboard.writeText(giftUrl) inside copyGiftUrl,
setCopied(true) only on success and log or surface an error on failure), store
the timeout id in a ref (e.g. copyTimeoutRef) instead of an ephemeral value,
call setTimeout to reset setCopied(false) and save its id, and add a useEffect
cleanup that clears the timeout via clearTimeout(copyTimeoutRef.current) when
the component unmounts so no dangling timers remain; update references to
copyGiftUrl, setCopied, and giftUrl accordingly.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 7333160a-941c-4b11-bd09-3ba1835bc997

📥 Commits

Reviewing files that changed from the base of the PR and between 7b87322 and 9543882.

⛔ Files ignored due to path filters (1)

• apps/admin-x-design-system/src/assets/icons/gift.svg is excluded by !**/*.svg

📒 Files selected for processing (3)

• apps/admin-x-settings/src/components/settings/membership/gift-subscriptions.tsx
• apps/admin-x-settings/src/components/settings/membership/membership-settings.tsx
• apps/admin-x-settings/src/components/sidebar.tsx