Update README with release instructions

Author: marckohlbrugge

README.md

@@ -37,10 +37,10 @@ fm draft send M9876543210
 
 ## Installation
 
-### Homebrew
+### Homebrew (recommended)
 
 ```bash
-brew install marckohlbrugge/tap/fm --HEAD
+brew install marckohlbrugge/tap/fm
 ```
 
 ### From Source
@@ -58,7 +58,7 @@ Then move `fm` to somewhere in your PATH, or add the directory to your PATH.
 ### Homebrew
 
 ```bash
-brew upgrade marckohlbrugge/tap/fm
+brew update && brew upgrade fm
 ```
 
 ### From Source
@@ -237,6 +237,26 @@ make build   # Build binary
 make test    # Run tests
 ```
 
+### Releasing
+
+To release a new version:
+
+```bash
+git tag v1.x.x
+git push origin v1.x.x
+```
+
+This triggers GitHub Actions to build binaries for macOS (Intel/ARM) and Linux (amd64/arm64) and create a GitHub release.
+
+Then update the Homebrew formula manually:
+
+```bash
+# Get checksums from the release
+gh release download v1.x.x --pattern 'checksums.txt' --output -
+
+# Update Formula/fm.rb in marckohlbrugge/homebrew-tap with new version and checksums
+```
+
 ## Contributing
 
 I'm not accepting pull requests at this time—reviewing external code for security in a tool that handles email requires more time than I can commit to. Feel free to [open an issue](https://github.com/marckohlbrugge/fastmail-cli/issues) for bug reports or feature requests.