feat: MongoDB partnership announcement top banner

[eldadfux]

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[greptile-apps]

Greptile Summary

This PR adds a MongoDB partnership announcement top banner (MongoPartnershipBanner.svelte) to the site's main layout and simultaneously removes the newsletter subscription feature — including Newsletter.svelte, blog/newsletter.svelte, the inline newsletter form on the community page, and the /subscription/verify route. The BANNER_KEY is rotated to mongodb-partnership-banner-01 so all users see the new banner on their next visit, and the --mongodb BEM modifier is added to the top-banner SCSS with MongoDB brand colours. The subscribeToNewsletter export in contact-partner.svelte is also correctly renamed to submitPartnerContact.

Key points:

• The new banner correctly inherits the [data-banner-hidden] CSS hide rule from the base .web-top-banner selector, so the localStorage dismiss mechanism is structurally intact (though the absence of a dismiss button — noted in a previous review — means it can never be triggered by the user).
• All newsletter component consumers are cleaned up consistently across the codebase.
• The deletion of /subscription/verify is the main concern: any newsletter verification emails already dispatched to users will now result in a 404 when clicked. This should be confirmed safe before deploying.

Confidence Score: 4/5

Mostly safe to merge, but should confirm no in-flight newsletter verification emails exist before deploying the subscription/verify route deletion.

The banner and SCSS changes are clean and the newsletter cleanup is internally consistent. The main open concern is the hard deletion of /subscription/verify without a redirect or tombstone page, which breaks stale verification email links. The previously flagged missing dismiss button also remains unaddressed.

src/routes/subscription/verify/+page.svelte (deleted) — confirm no pending verification emails before deploying.

Important Files Changed

Filename	Overview
src/lib/components/MongoPartnershipBanner.svelte	New top banner for the MongoDB partnership announcement; renders correctly and respects the [data-banner-hidden] SCSS rule, but has no dismiss button (flagged in previous threads).
src/lib/constants.ts	BANNER_KEY rotated to 'mongodb-partnership-banner-01' so all users see the new banner fresh; Banners union type updated accordingly.
src/lib/layouts/Main.svelte	Swaps AnnouncementBanner/HackathonBanner imports for MongoPartnershipBanner and mounts it at the top of the layout.
src/scss/7-components/_top-banner.scss	Adds --mongodb BEM modifier with MongoDB brand colours; [data-banner-hidden] hide rule is inherited from the parent selector and works correctly.
src/routes/subscription/verify/+page.svelte	Deleted; breaks any in-flight newsletter verification email links — worth confirming no pending verifications remain before deploying.
src/routes/partners/catalog/(components)/contact-partner.svelte	Exported function renamed from misleading subscribeToNewsletter to submitPartnerContact — purely a clarifying rename, no logic change.
src/routes/community/+page.svelte	Inline newsletter subscription form removed cleanly along with its state variables, submit handler, and imports.
src/markdoc/layouts/Post.svelte	Newsletter component removed from blog post footer; clean change with no orphaned references.
src/lib/components/index.ts	Newsletter barrel export removed; consistent with the component deletion.

Comments Outside Diff (1)

1. src/routes/subscription/verify/+page.svelte

   Deleting verify page breaks in-flight verification emails

   The /subscription/verify route is being deleted alongside the newsletter components. Any verification emails that were already dispatched to users (but not yet clicked) will now result in a 404 when they follow the link. The newsletter/verify POST to the growth endpoint also becomes unreachable on the client side.

   If there is a guarantee that no verification emails are in-flight at deploy time (e.g. the growth-endpoint subscription queue has been drained, or this path was never actively sending), this is safe to remove. Otherwise, consider keeping a minimal redirect or "subscription removed" page at this route to handle stale email links gracefully before deleting it.

_{Reviews (2): Last reviewed commit: "change banner colors" | Re-trigger Greptile}