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/package.json

@@ -0,0 +1,33 @@
+{
+  "name": "maarcadetweet-app",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview",
+    "check": "svelte-check --tsconfig ./tsconfig.json",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "tauri": "tauri"
+  },
+  "packageManager": "npm@10.8.2",
+  "dependencies": {
+    "@tauri-apps/api": "^2.1.1",
+    "@tauri-apps/plugin-notification": "^2.0.1",
+    "@tauri-apps/plugin-dialog": "^2.0.1"
+  },
+  "devDependencies": {
+    "@sveltejs/vite-plugin-svelte": "^4.0.2",
+    "@tauri-apps/cli": "^2.1.0",
+    "@tsconfig/svelte": "^5.0.4",
+    "svelte": "^5.2.0",
+    "svelte-check": "^4.1.0",
+    "tslib": "^2.8.0",
+    "typescript": "^5.6.3",
+    "vite": "^5.4.10",
+    "vitest": "^2.1.0",
+    "vite-plugin-static-copy": "^1.0.6"
+  }
+}