maarcadetweet: initial commit

AT Protocol PDS + AppView + Tauri Desktop Client, 160-char post limit.

- PDS (Rust + axum + sqlx)
  - Auth: createAccount, createSession, refreshSession
  - Records: createRecord, deleteRecord (race-safe via SELECT FOR UPDATE)
  - Feed: feed.like.create, feed.repost.create
  - Sync: getRepo, getBlocks, getLatestCommit, getRecord (with MST proof), listRepos
  - Identity: resolveHandle
  - MST: spec-conformant (at-mst crate, 27 tests)
  - Repo: signed commits, TID counter (monotonic, 4096 wrap safe)

- AppView (Rust + axum + sqlx)
  - Jetstream consumer (WebSocket, exponential backoff, 38k+ events indexed)
  - REST API: timeline/home (graph-aware), profile, search, post (with thread hydration)
  - Handle-sync worker (did:plc + did:web)
  - JSONB embed storage + thread columns (migration 0003)
  - Like/repost counter cache (migration 0004)

- Tauri 2 + Svelte 5 Desktop Client
  - System tray (Show/Compose/Quit menu)
  - OS notifications (tauri-plugin-notification)
  - Auto-update (tauri-plugin-updater, placeholder endpoint)
  - Window-state (tauri-plugin-window-state)
  - 160-char compose with live counter
  - Image/Link embed rendering
  - LocalStorage-persisted like state
  - Timeline with poll (prepend new posts)
  - Custom TitleBar (transparent, no decorations)
  - Orange/IBM Plex Mono maarcade design

Tests: 231 Rust + 9 vitest = 240 passed.

crates/tauri-app/src/lib/components/Terminal.svelte

@@ -0,0 +1,60 @@
+<script lang="ts">
+  let { children, title = "maarcadetweet" }: { children?: any; title?: string } = $props();
+</script>
+
+<div class="terminal">
+  <div class="terminal__bar">
+    <div class="terminal__dots">
+      <i></i><i></i><i></i>
+    </div>
+    <div class="terminal__title">{title}</div>
+    <div class="terminal__bar-spacer"></div>
+  </div>
+  <div class="terminal__body">
+    {@render children?.()}
+  </div>
+</div>
+
+<style>
+  .terminal {
+    background: var(--bg-deep);
+    border: 1px solid var(--line-2);
+    border-radius: var(--r-lg);
+    overflow: hidden;
+    box-shadow: 0 24px 60px -28px rgba(0, 0, 0, 0.8);
+  }
+  .terminal__bar {
+    display: flex;
+    align-items: center;
+    gap: var(--s-3);
+    padding: var(--s-3) var(--s-4);
+    background: var(--bg-elev);
+    border-bottom: 1px solid var(--line);
+  }
+  .terminal__dots {
+    display: flex;
+    gap: 7px;
+  }
+  .terminal__dots i {
+    width: 11px;
+    height: 11px;
+    border-radius: var(--r-pill);
+    background: var(--line-2);
+    display: block;
+  }
+  .terminal__dots i:first-child { background: #4a4a4a; }
+  .terminal__title {
+    font-family: var(--font-mono);
+    font-size: var(--fs-50);
+    color: var(--text-dim);
+    margin-inline: auto;
+    letter-spacing: 0.02em;
+  }
+  .terminal__bar-spacer { width: 36px; }
+  .terminal__body {
+    font-family: var(--font-mono);
+    font-size: 0.95rem;
+    line-height: 1.85;
+    padding: var(--s-5);
+  }
+</style>