Pinned repos: sidebar section with quick access

[Flo0806]

Problem

Users frequently switch between the same few repos. Every time they have to search or scroll to find them. There's no way to bookmark/pin repos for quick access.

Goal

Add a pinned repos section in the sidebar that gives one-click access to frequently used repositories.

Proposed UX

Sidebar

• New collapsible section in the left sidebar (below navigation, above auth)
• Icon: paperclip (i-lucide-paperclip)
• Collapsed: shows paperclip icon only
• Expanded: shows list of all pinned repos with unpin button
• Clicking a pinned repo navigates to the issues overview with that repo selected

Pinning

• Pin button available in the repo selector (IssueRepoSelect) next to each repo
• Works for both owned and external repos
• Pinned state persists across sessions via user settings

Data

• Add pinnedRepos: string[] to UserSettings in shared/types/settings.ts
• Default: []
• Stored in KV storage alongside existing settings (theme, primaryColor, locale, selectedRepo)
• Settings API already supports partial updates — just needs the new field

Mockup

Sidebar (expanded):
┌──────────────────────┐
│ 📎 Pinned repos      │
│  nuxt/nuxt        ✕  │
│  vuejs/core       ✕  │
│  my-org/api       ✕  │
└──────────────────────┘

Affected files

• shared/types/settings.ts — add pinnedRepos to UserSettings + defaults
• app/components/ui/SideBar.vue — new pinned repos section
• app/components/issue/IssueRepoSelect.vue — add pin/unpin button per repo
• app/composables/useUserSettings.ts — no changes needed (already handles partial updates)