docs: add install-from-repo and update instructions

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -3,14 +3,46 @@
 Local dev-environment monitor. AWS auth state, docker containers, git repo status.
 Two modes: one-shot commands, or a live refreshing TUI dashboard.
 
-## Build
+## Install
+
+Requires Go 1.25+. Two ways:
+
+**A. Clone + build** (simplest):
 
 ```sh
+git clone git@git.abrell.se:victor/mydev.git
+cd mydev
 go build -o mydev .
-# optional: put it on PATH
-mv mydev ~/go/bin/   # or /usr/local/bin
+sudo mv mydev /usr/local/bin/        # on PATH
 ```
 
+**B. `go install` from the repo** (private host, so configure auth once):
+
+```sh
+go env -w GOPRIVATE=git.abrell.se                                   # skip proxy/checksum DB
+git config --global url."git@git.abrell.se:".insteadOf "https://git.abrell.se/"   # use SSH
+go install git.abrell.se/victor/mydev@latest                        # → ~/go/bin/mydev
+```
+
+Make sure `~/go/bin` is on your `PATH` for option B
+(`export PATH="$HOME/go/bin:$PATH"`).
+
+## Updating
+
+When new changes are pushed:
+
+- **Clone + build:** `git pull && go build -o mydev . && sudo mv mydev /usr/local/bin/`
+- **go install:** `go install git.abrell.se/victor/mydev@latest`
+
+`@latest` resolves to the newest **git tag** (e.g. `v1.2.0`), or the latest commit
+on `main` if there are no tags. To cut a release, tag and push:
+
+```sh
+git tag v1.0.0 && git push --tags
+```
+
+Then everyone gets it with `go install …@latest` (or pin a version with `@v1.0.0`).
+
 ## Configure (required for `status` / `dash`)
 
 Repo locations live in a config file — no default, no flag. First run: