Expand README with comprehensive documentation

README.md

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 # Cartesi Homebrew Tap
 
+Homebrew formulae for [Cartesi](https://cartesi.io) tooling: the Cartesi Machine emulator, its
+kernel and rootfs images, the Cartesi CLI, and supporting build tools.
+
+## Installation
+
+Add the tap and trust it:
+
 ```shell
 brew tap cartesi/tap
+brew trust cartesi/tap
+```
+
+Then install any of the formulae below:
+
+```shell
+brew install cartesi-machine
 ```
 
-For more information, visit https://docs.cartesi.io
+You can also use the fully qualified name:
+
+```shell
+brew install cartesi/tap/cartesi-machine
+```
+
+### About `brew trust`
+
+Since [Homebrew 6.0.0](https://brew.sh/2026/06/11/homebrew-6.0.0/), third-party taps must be
+explicitly trusted before Homebrew will evaluate any of their code. Tapping alone is not enough —
+until you trust it, Homebrew ignores this tap's formulae and reports:
+
+```
+Warning: The following taps are not trusted: cartesi/tap
+Homebrew is currently ignoring formulae, casks and commands from these taps because tap trust is
+required.
+```
+
+Trusting is a deliberate step, not a prompt you can click through, because a tap can run arbitrary
+unsandboxed Ruby on your machine. If you would rather not trust the whole tap, trust individual
+formulae instead:
+
+```shell
+brew trust --formula cartesi/tap/cartesi-machine
+```
+
+Use `brew trust` to list what you have trusted and `brew untrust cartesi/tap` to revoke it. On
+Homebrew 5.x and earlier there is no `brew trust` command and no trust step is needed.
+
+## Formulae
+
+| Formula | Description |
+| --- | --- |
+| [`cartesi`](Formula/cartesi.rb) | CLI for developing Cartesi applications ([cartesi/cli](https://github.com/cartesi/cli)) |
+| [`cartesi-machine`](Formula/cartesi-machine.rb) | Metapackage that pulls in the emulator plus the Linux and rootfs images |
+| [`cartesi-machine-emulator`](Formula/cartesi-machine-emulator.rb) | Off-chain implementation of the Cartesi Machine ([cartesi/machine-emulator](https://github.com/cartesi/machine-emulator)) |
+| [`cartesi-machine-linux-image`](Formula/cartesi-machine-linux-image.rb) | Kernel image for the Cartesi Machine ([cartesi/machine-linux-image](https://github.com/cartesi/machine-linux-image)) |
+| [`cartesi-machine-rootfs-image`](Formula/cartesi-machine-rootfs-image.rb) | Rootfs image for the Cartesi Machine ([cartesi/machine-guest-tools](https://github.com/cartesi/machine-guest-tools)) |
+| [`xgenext2fs`](Formula/xgenext2fs.rb) | Ext2 filesystem generator for embedded systems ([cartesi/genext2fs](https://github.com/cartesi/genext2fs)) |
+
+`cartesi-machine` is the recommended entry point: it is a metapackage with no files of its own that
+depends on the emulator and both images, so a single install gives you a machine that boots out of
+the box.
+
+### Usage
+
+Install the machine and run it:
+
+```shell
+brew install cartesi-machine
+cartesi-machine --version
+cartesi-machine -- "echo hello from inside the machine"
+```
+
+Install the CLI to scaffold and run applications:
+
+```shell
+brew install cartesi
+cartesi --version
+```
+
+The image formulae install their payloads into `$(brew --prefix)/etc/cartesi/images`, symlinked as
+`linux.bin` and `rootfs.ext2`. The emulator is configured at build time to look there, so it picks
+up the images automatically once both formulae are installed.
+
+## Supported platforms
+
+Prebuilt bottles are published to `ghcr.io/v2/cartesi/tap` for Apple Silicon macOS (Sequoia and
+Tahoe). The images and the metapackage ship platform-independent bottles.
+
+On any other platform — Intel macOS or Linux — Homebrew falls back to building from source, which
+requires the usual toolchain and the build dependencies declared in each formula. Building the
+emulator from source can take several minutes.
+
+## Updating and uninstalling
+
+```shell
+brew update
+brew upgrade cartesi-machine
+
+brew uninstall cartesi-machine
+brew untap cartesi/tap
+```
+
+## Contributing
+
+Formula changes are made via pull request against `main`.
+
+1. Edit the formula under `Formula/` — bump `url`/`sha256` for a new upstream release, or bump
+   `revision` when only the packaging changes.
+2. Open a pull request. The `brew test-bot` workflow runs `brew audit`, `brew install`, and the
+   formula's `test do` block on every supported macOS runner, and uploads the resulting bottles as
+   build artifacts.
+3. Once CI is green, a maintainer applies the `pr-pull` label. That triggers `brew pr-pull`, which
+   downloads the bottles from the run, uploads them to the GitHub Packages registry, commits the
+   updated `bottle do` blocks, and pushes to `main`.
+
+Do not commit `bottle do` checksums by hand — `brew pr-pull` generates them from the bottles CI
+actually built.
+
+To test a local change before opening a pull request:
+
+```shell
+brew install --build-from-source ./Formula/<formula>.rb
+brew test ./Formula/<formula>.rb
+brew audit --strict --online ./Formula/<formula>.rb
+```
+
+## Troubleshooting
+
+- **`Warning: The following taps are not trusted`**, or formulae from the tap not being found at all
+  on Homebrew 6.0+ — run `brew trust cartesi/tap`. See [About `brew trust`](#about-brew-trust).
+- **`Error: No available formula with the name ...`** — run `brew update` to refresh the tap, and
+  check the tap is trusted.
+- **A bottle is missing for your platform** — pass `--build-from-source` to build locally.
+- **Stale images after an upgrade** — `brew reinstall cartesi-machine-linux-image
+  cartesi-machine-rootfs-image` recreates the symlinks under `etc/cartesi/images`.
+
+## More information
+
+- Documentation: https://docs.cartesi.io
+- Cartesi on GitHub: https://github.com/cartesi