Add pinned statuses to profile

[cbl]

Adds pinned-statuses support to profile pages (read-side). Most-recently-pinned post renders as a full Status with a "Pinned" indicator; additional pins (up to 5 total, per Mastodon) appear in a compact row below. Plus two polish fixes to Status.vue spacing that surfaced during review.

Pinned section

• Primary + overflow pattern. The newest pin is rendered as a full Status (readable long-form text). If there are 2–5 pins, the rest appear as small preview cards below. Avoids the 5-stacked-posts scroll problem while respecting user curation.
• Mobile (< md): horizontal snap-scroll, cards fixed at 220px, left-indented 72px so the first card aligns with the primary pin's text content (under the avatar).
• Desktop (md+): switches to a 2-column grid. No chevron controls — with max 4 overflow cards, everything fits without scrolling. Matches App Store / Stripe "content row" patterns for wide viewports.
• Dedupe: pinned IDs filtered out of the chronological timeline so no post appears twice.
• Only on the default Posts tab (web). Replies/Media tabs stay chronological — pins that are replies show naturally in Replies, etc. Matches Twitter's rule.
• No empty state noise: if a profile has only pinned posts and no chronological posts, the "No posts yet" state is suppressed.

Added

• packages/api/src/composables/queries/useAccountData.ts — getAccountPinnedStatuses(acct) calls accounts.statuses.list({ pinned: true, limit: 5 }).
• packages/api/src/composables/useAccount.ts — extended mobile composable with pinnedStatuses ref, fetched in parallel with recent statuses via Promise.all.
• packages/api/src/mock/handlers/accounts.ts — mock handler supports ?pinned=true.
• packages/api/src/mock/fixtures/statuses.ts — jane@ has 3 pins, sarah@ has 1, so overflow-row and single-pin cases are both testable in mock mode.
• packages/ui/src/components/status/Status.vue — isPinned prop. Renders a pushpin-icon header row using the same slot as the reblog indicator.
• packages/ui/src/components/status/PinnedOverflowCard.vue — compact card (~220px) with pushpin micro-label, 3-line content excerpt, media count indicator. Accepts a class prop so the parent controls width.
• packages/ui/src/components/status/PinnedSection.vue — coordinates primary + overflow, forwards all Status action events.
• apps/web/app/components/ProfilePinnedSection.vue — thin wrapper that wires useWebActions (mirror of StatusTimeline.vue's pattern).
• apps/web/app/pages/@[acct]/index.vue — fetches pinned + chronological in parallel, dedupes, renders both.
• apps/mobile/src/pages/Profile.vue — dedupe + render; mobile has no tabs so pins sit above the flat list.

Polish fixes to Status.vue

Surfaced while staring at the pinned section, but affect every feed:

• Symmetric vertical padding. StatusActions's ButtonAction adds pb-2 (8px) for tap-target extension, which meant the visual gap below the action icons was 20px while the gap above the display name was only 12px. Changed the content column from py-3 to pt-3 pb-1 when actions render (preserved pb-3 when hideActions=true for thread ancestors). Top and bottom now both visually 12px.
• Tighter indicator-to-post gap. The "Pinned" / "X reposted" label was separated from the post header by 12px, making it feel like its own block instead of a caption attached to the post. When hasIndicator is true, content column's top padding drops from pt-3 to pt-1 (4px), matching Twitter/Bluesky's tight caption-style spacing.

Out of scope

• Pin / unpin action (write-side) — follow-up PR will add "Pin to profile" / "Unpin from profile" to the status actions menu for own posts.
• Profile tabs on mobile — mobile profile is still a single flat list, pins just render above it.