docs: rewrite README for v0.3.0 (install, sign-in, private URLs)

README.md

@@ -1,14 +1,31 @@
 # PixelVault Desktop
 
+[![Release](https://img.shields.io/github/v/release/pixelvault-dev/desktop)](https://github.com/pixelvault-dev/desktop/releases/latest)
+[![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE)
+![Platform](https://img.shields.io/badge/platform-macOS%20%7C%20Linux-lightgrey)
+![Built with Tauri](https://img.shields.io/badge/built%20with-Tauri%20v2-24C8DB)
+
 A macOS/Linux **menubar app**: copy an image, and a hosted URL replaces it on
 your clipboard — ready to paste into a coding agent that only accepts text
 (Codex cloud, Claude Code on the web, Cursor background agents, Daytona/e2b
 sandboxes). The remote side needs nothing installed; it just receives a URL.
 
-> **Status: v0 (slices 1–2).** Passive clipboard watch + active-hotkey capture →
-> keyless upload → URL on clipboard. macOS-first. No sign-in yet (planned),
-> Linux build pending. See `docs/specs/clipboard-desktop-app.md` in the main
-> PixelVault repo.
+## Install
+
+**macOS** — [Homebrew](https://brew.sh):
+
+```bash
+brew install --cask pixelvault-dev/tap/pixelvault
+```
+
+Or download the latest **`PixelVault_*_universal.dmg`** from the
+[Releases page](https://github.com/pixelvault-dev/desktop/releases/latest)
+(one bundle for both Intel and Apple Silicon). Builds are currently **unsigned**,
+so on first launch **right-click the app → Open** to get past Gatekeeper.
+
+**Linux** — grab the latest **`.AppImage`**, **`.deb`**, or **`.rpm`** from
+[Releases](https://github.com/pixelvault-dev/desktop/releases/latest). (macOS is
+the primary target; Linux builds but is less battle-tested.)
 
 ## How it works
 
@@ -18,26 +35,36 @@ Two ways to get an image, one result — a hosted URL on your clipboard:
   **image** appears, it's uploaded and the **hosted URL** replaces it. On macOS,
   **⇧⌃⌘4** copies a screen region straight to the clipboard (note the `Ctrl` —
   plain ⇧⌘4 saves a file to the Desktop and won't be picked up).
-- **Mode B (active hotkey):** press **⇧⌘2** — the app invokes macOS's native
-  `screencapture -i` (the same crosshair region select), captures to a temp file,
-  uploads it, and puts the URL on your clipboard.
+- **Mode B (active hotkey):** press **⇧⌘2** — the app runs macOS's native region
+  capture (`screencapture -i`, the same crosshair select), uploads the grab, and
+  puts the URL on your clipboard.
+
+Uploads take ~0.5–2s. The **"Image URL copied" notification is your cue** that the
+clipboard now holds the URL — then **⌘V** to paste. A `⋯` on the menu-bar icon
+means an upload is in flight.
+
+## Accounts & privacy
 
-In both modes the upload takes ~0.5–2s. The **"Image URL copied" notification is
-your cue** that the clipboard now holds the URL — then **⌘V** to paste. While an
-upload is in flight the menu-bar icon shows a `⋯` busy indicator.
+- **Without signing in:** an anonymous free trial — **5 uploads**, after which the
+  app prompts you to sign in. Links are public and **time-limited (~30 days)**.
+- **Sign in** (device login — no password) for **keyed uploads with no trial
+  gate**, a **Recent uploads** history in the tray menu, and optional **private,
+  signed URLs** (a toggle in Settings — the app hands you a ready-to-paste signed
+  link).
 
-Anonymous uploads are **temporary (~30 days)**. The tray shows your remaining
-free uploads; sign-in for permanent uploads + history is coming.
+Links are time-limited by design — this is a *paste-into-your-agent* tool, not
+long-term hosting. For permanent image hosting, use
+[PixelVault](https://pixelvault.dev) directly (API, dashboard, and a free tier).
 
-## Develop
+## Build from source
 
 Prerequisites: [Rust](https://rustup.rs), Node 18+, and Xcode Command Line Tools
 (macOS).
 
 ```bash
 npm install
 npm run tauri dev      # run the app
-npm run tauri build    # produce a bundle
+npm run tauri build    # produce a bundle (.dmg on macOS; .AppImage/.deb/.rpm on Linux)
 ```
 
 Point at a non-production API while testing:
@@ -49,8 +76,8 @@ PIXELVAULT_API_BASE=https://api-staging.pixelvault.dev npm run tauri dev
 ## Stack
 
 Tauri v2 (Rust core + system webview). Clipboard I/O via `arboard`, PNG encoding
-via `image`, uploads via blocking `reqwest`. The UI is the tray menu; the small
-window is a status/settings surface.
+via `image`, uploads via blocking `reqwest`. The tray menu is the primary UI; the
+small window is a status/settings surface.
 
 ## License