docs(website): reconcile installation docs with v0.2.0 shipped reality

installation.md predated the install/packaging work that landed on main:
- drop the "once published" placeholders now that v0.2.0 is live
- fix the Homebrew/Scoop commands (tap/bucket-add forms; the bare
  `brew install rdbms-playground` was wrong)
- add the curl|sh and PowerShell one-line installers (ADR-0055),
  `cargo install` / `cargo binstall` (ADR-0056), and prebuilt binaries
- present winget as coming-soon (PR awaiting the public catalogue)

command-line-options.md: add `-V`/`--version` and the in-app `version`
command (ADR-0054).

website/src/content/docs/getting-started/installation.md

@@ -1,6 +1,6 @@
 ---
 title: Installation
-description: Install RDBMS Playground from a prebuilt binary or a package manager, and run it for the first time.
+description: Install RDBMS Playground with a one-line installer, a package manager, cargo, or a prebuilt binary.
 sidebar:
   order: 1
 ---
@@ -9,34 +9,86 @@ RDBMS Playground is a single self-contained program. There is nothing to
 configure and no separate database to install — everything it needs is
 built in.
 
-## Prebuilt binaries
+Pick whichever method suits your platform. The one-line installers are the
+quickest if you just want to get going.
 
-Download the binary for your platform, make it executable if needed, and
+## One line
-put it somewhere on your `PATH`.
 
-:::note
+These download the matching binary for your machine, verify its checksum,
-Download links are published with each release. They are added here when the
+and put it on your `PATH`.
-first public version ships.
+
-:::
+### Linux & macOS
+
+```sh
+curl -fsSL https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh | sh
+```
+
+It detects your operating system and CPU, installs to `~/.local/bin`, and
+prints a hint if that directory isn't on your `PATH`. Set
+`RDBMS_INSTALL_DIR` to install somewhere else, or `RDBMS_VERSION=vX.Y.Z` to
+pin a specific version. Prefer to read a script before running it? It lives
+at [`scripts/install.sh`](https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh).
+
+### Windows (PowerShell)
+
+```powershell
+irm https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.ps1 | iex
+```
+
+It downloads the matching `.exe`, verifies its checksum, installs to
+`%LOCALAPPDATA%\Programs\rdbms-playground`, and adds that folder to your
+user `PATH`. Use `-InstallDir` to choose a different location or `-Version`
+to pin a release.
 
 ## Package managers
 
-Once published, the playground will be installable through common package
+### Homebrew (macOS & Linux)
-managers:
 
 ```sh
-# macOS / Linux (Homebrew)
+brew tap lazyeval/tap https://git.lazyeval.net/lazyeval/homebrew-tap
-brew install rdbms-playground
+brew install lazyeval/tap/rdbms-playground
+```
 
-# Windows (Scoop)
+### Scoop (Windows)
+
+```sh
+scoop bucket add lazyeval https://git.lazyeval.net/lazyeval/scoop-bucket
 scoop install rdbms-playground
 ```
 
+### winget (Windows)
+
 :::note
-Package-manager availability lands with the first public release; the exact
+A winget package (`winget install LazyEvaluation.RdbmsPlayground`) is on its
-names are confirmed here at that time.
+way and awaiting review in the public winget catalogue. Until it lands, use
+Scoop or the PowerShell one-liner above.
 :::
 
+## With cargo
+
+If you have a Rust toolchain, you can install from
+[crates.io](https://crates.io/crates/rdbms-playground):
+
+```sh
+cargo install rdbms-playground
+```
+
+For a faster install that fetches a prebuilt binary instead of compiling,
+use [`cargo-binstall`](https://github.com/cargo-bins/cargo-binstall)
+(install it first — it is not part of `cargo` itself):
+
+```sh
+cargo binstall rdbms-playground
+```
+
+## Prebuilt binaries
+
+Every release publishes static Linux, standalone Windows, and macOS
+binaries (x86_64 and aarch64), each with a `.sha256` checksum, on the
+[releases page](https://git.lazyeval.net/oli/rdbms-playground/releases).
+Download the one for your platform, make it executable if needed, and put
+it somewhere on your `PATH`.
+
 ## Run it
 
 Start the playground with no arguments and it opens a fresh, automatically
@@ -60,5 +112,9 @@ Useful options (run `rdbms-playground --help` for the full list):
 | `--data-dir <PATH>` | Use a different location for stored projects. |
 | `--theme <light\|dark>` | Force a theme instead of auto-detecting. |
 | `--mode <simple\|advanced>` | Start in a specific input mode. |
+| `--version` | Print the version and exit. |
+
+The full list, with examples, is on the
+[command-line options](/using-the-playground/command-line-options/) page.
 
 Next: [create your first project](/getting-started/first-project/).

website/src/content/docs/using-the-playground/command-line-options.md

@@ -29,8 +29,13 @@ rdbms-playground path/to/project
 | `--no-undo` | Disable the undo machinery for this run — no snapshot is taken before each change (see [Undo, redo & history](/using-the-playground/undo-and-history/)). |
 | `--demo` | Turn on demonstration mode — a teaching aid that briefly shows an on-screen badge for keys that otherwise leave no visible mark (Tab, Enter, the arrows, and the like). Useful for screencasts and for demonstrating the playground to a class. Off by default. |
 | `--log-file <PATH>` | Write diagnostic logging to `PATH`. |
+| `-V`, `--version` | Print the version and exit. |
 | `-h`, `--help` | Print the usage banner and exit. |
 
+Once the playground is running, the `version` command prints the same
+version line into the output panel — handy when you want to note which
+version you're on without leaving the app.
+
 ## Examples
 
 ```sh