[Fix] Hide admin-only Slack/Linear connect cards from members

[daniel-lxs]

Problem

The home page onboarding cards "Chat with Roomote on Slack" and "Assign tasks to agents from Linear" in OnboardingCard.tsx are shown to every signed-in user, but their "Do it" actions call slack.connectApp / linear.connectApp, which are admin-gated server-side (assertAdminResult) and return { success: false, error: 'Unauthorized' } for members. A member clicking "Do it" hits a dead end with no path forward.

Repro: with a role='member' user and no active Slack installation, load / — the Slack card shows, and clicking "Do it" POSTs slack.connectApp, which returns Unauthorized.

Fix

Gate both cards on isAdmin (already available in the component), consistent with how the deployment-scoped MCP cards in the same file are gated. Members instead see the next applicable card (e.g. the member-appropriate "Link your GitHub so Roomote acts as you").

Other cards in the file were checked for the same pattern: the GitHub link card uses the non-admin-gated personal linking mutation, the promoted MCP cards already filter deployment-scoped integrations on isAdmin, and the automations card is already effectively hidden for members because automations.onboardingStatus throws for non-admins.

Verification

Verified locally against a running instance with the Slack installation deactivated:

• Admin: the Slack card still appears (no regression).
• Member: the Slack and Linear cards no longer appear; the GitHub link card correctly takes their place.
• check-types:fast, oxlint, and oxfmt pass.

🤖 Generated with Claude Code

[roomote-roomote]

No code issues found. See task

_{Reviewed 5a1ddb1}