[kulmann]

Description

Replaces the small "Sponsor us" text link at the bottom of the sidebar with a prominent "Support OpenCloud" card.

• "Donate" links to the GitHub sponsors page (same target as before).
• "Buy support" links to the subscription support page on the OpenCloud website, in German if a German UI language is selected and in English otherwise.
• The card uses the tertiary color roles, so it follows the active theme including dark mode.
• The heart icon animates once after page load and respects prefers-reduced-motion.
• The card is also shown in the mobile navigation menu.
• The existing disableSponsorLink config option hides the whole card.

Keeping this as a draft until the mtm params are confirmed and I've received permalinks for the buy support URLs.

Related Issue

• Fixes https://github.com/opencloud-eu/internal/issues/358 (bug: support link is barely visible)

Screenshots

How Has This Been Tested?

• test environment: unit tests (Vitest)
• test case 1: card is rendered by default and hidden when disableSponsorLink is set
• test case 2: donate button links to the GitHub sponsors page in a new tab
• test case 3: buy support button links to the German page for de/de_CH and to the English page for other languages
• test case 4: animation only runs on the first mount

[AlexAndBear]

Suggested change

	<support-card v-if="!options.disableSponsorLink" class="mx-2" />
	<support-card v-if="!options.disableSponsorLink" class="mx-3 pt-4" />

to have the same width as the nav bar items and some padding top when the window heigh gets narrow

[AlexAndBear]

I'd also remove the pb-4 from the version info so looks more harmonized

[AlexAndBear]

Heads-up: #4370 hides the sidebar footer (sponsor link, version, version check) in embed mode. The support card here sits outside that footer, so it'll need the same check, e.g. v-if="!options.disableSponsorLink && !isEmbedModeEnabled" with useEmbedMode(). Whichever lands second gets a small conflict in SidebarNav.vue.

[AlexAndBear]

@kulmann how do we go around this show-stopper?