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.

.env.example

@@ -0,0 +1,42 @@
+# =====================================================
+# maarcadetweet — environment
+# =====================================================
+# Copy to .env and adjust.
+
+# --- General ---
+RUST_LOG=info,maarcadetweet=debug,sqlx=warn
+APP_ENV=dev
+
+# --- PDS server ---
+PDS_HOST=127.0.0.1
+PDS_PORT=2583
+PDS_PUBLIC_URL=http://127.0.0.1:2583
+PDS_HANDLE_DNS_ZONE=.maarcadetweet.local
+PDS_JWT_SECRET=change-me-to-a-32-byte-random-string-please
+
+# --- AppView service ---
+APPVIEW_HOST=127.0.0.1
+APPVIEW_PORT=2584
+APPVIEW_PUBLIC_URL=http://127.0.0.1:2584
+JETSTREAM_URL=wss://jetstream1.us-east.bsky.network/subscribe
+# Collections the AppView will index
+JETSTREAM_COLLECTIONS=app.bsky.feed.post,app.bsky.feed.like,app.bsky.feed.repost,app.bsky.graph.follow
+
+# --- Databases ---
+DATABASE_URL_PDS=postgres://pds:pds@127.0.0.1:5434/pds
+DATABASE_URL_APPVIEW=postgres://appview:appview@127.0.0.1:5435/appview
+
+# --- Blob store (S3 / MinIO) ---
+S3_ENDPOINT=http://127.0.0.1:9100
+S3_REGION=us-east-1
+S3_ACCESS_KEY=minioadmin
+S3_SECRET_KEY=minioadmin
+S3_BUCKET_PDS=maarcadetweet-pds
+S3_BUCKET_APPVIEW=maarcadetweet-appview
+
+# --- PLC Directory (dev: leave default; can mock) ---
+PLC_DIRECTORY_URL=https://plc.directory
+# PLC_DIRECTORY_URL=http://127.0.0.1:2582
+
+# --- AppView ingest auth (optional, dev ok if unset) ---
+# APPVIEW_INGEST_SECRET=change-me-to-a-shared-secret-between-pds-and-appview