fix: group catalog apps under Projects menu

[Official-Krish]

Summary

Groups catalog app deployments under the Projects menu so all deployments are managed in one place, removing the confusing separate Apps entry point.

Motivation

Catalog apps (N8N, Convex, etc.) were created as projects with isApp=true, but the UI hid them under a separate Apps menu item. Regular deployments showed under Projects, so users with a mix of catalog apps and custom services saw an incomplete list and believed deployments were missing. This merges both into one view.

Related issue

#558

Changes

• apps/dashboard/src/lib/sidebar-nav.ts — remove apps entry from the main rail
• apps/dashboard/src/lib/sidebar-nav.test.ts — update rail expectations
• apps/dashboard/src/components/sidebar.tsx — collapse Projects/Apps counts into a single total project count
• apps/dashboard/src/app/(dashboard)/projects/page.tsx — include catalog apps in the Projects list
• apps/dashboard/src/app/(dashboard)/DashboardHomeClient.tsx — merge the home-page Apps card into the Your Projects card
• apps/dashboard/src/components/overview/home-tips.ts — point the Apps home tip to /library
• apps/dashboard/src/app/(dashboard)/apps/page.tsx — redirect /apps to /projects
• apps/dashboard/src/app/(dashboard)/library/page.tsx — add an Apps tab to the New Project flow that renders the app catalog

Screenshots

Before

After

Checklist

• One change per PR — one bug, or one agreed feature, with nothing unrelated bundled in
• The diff is scoped — no reformatting or lint fixes on lines I wasn't otherwise changing
• A test fails without this change and passes with it (or I explained above why there isn't one)
• bun run test, bun run --cwd <workspace> lint, and bun format all pass locally
• I understand every line of this diff and can explain it in review