Add interactive Agrarian build menu

doc/README.md

@@ -37,6 +37,7 @@ The following are developer notes on how to build Agrarian Core on your native p
 
 - [Dependencies](dependencies.md)
 - [Agrarian 2.0 Modernization Status](modernization.md)
+- [Interactive Build Menu](build-menu.md)
 - [Ubuntu 24.04 Build Notes](build-ubuntu-24.md)
 - [Desktop Wallet Build Quick Start](build-wallets.md)
 - [macOS Build Notes](build-osx.md)

doc/build-menu.md

@@ -0,0 +1,65 @@
+Interactive Build Menu
+======================
+
+`contrib/agrarian-build-menu.sh` provides an interactive Ubuntu build workflow
+for common Agrarian targets:
+
+- Linux daemon and CLI tools
+- Linux Qt GUI wallet
+- Windows daemon and CLI tools
+- Windows Qt GUI wallet
+
+The script clones the Agrarian repository if the selected checkout directory
+does not exist. If the checkout already exists, it fetches, checks out the
+configured branch, and performs a fast-forward pull.
+
+Quick Start
+-----------
+
+From an existing checkout:
+
+    ./contrib/agrarian-build-menu.sh
+
+From a fresh Ubuntu host:
+
+    sudo apt-get update
+    sudo apt-get install -y git ca-certificates
+    git clone --branch 2.0 https://github.com/pacificao/agrarian.git agrarian
+    cd agrarian
+    ./contrib/agrarian-build-menu.sh
+
+Defaults
+--------
+
+The script can be configured with environment variables:
+
+    REPO_URL=https://github.com/pacificao/agrarian.git
+    BRANCH=2.0
+    WORKDIR=$HOME/agrarian
+    JOBS=1
+
+Example:
+
+    JOBS=8 WORKDIR=$HOME/src/agrarian ./contrib/agrarian-build-menu.sh
+
+Linux Daemon Autostart
+----------------------
+
+After a Linux daemon-capable build, the script asks whether to install and start
+`agrariand` for the current user. If accepted, it creates:
+
+- `$HOME/.local/bin/agrariand`
+- `$HOME/.local/bin/agrarian-cli`
+- `$HOME/.agrarian/agrarian.conf`
+- `$HOME/.config/systemd/user/agrariand.service`
+
+It then enables and starts the user service with:
+
+    systemctl --user enable --now agrariand.service
+
+Windows Build Output
+--------------------
+
+For Windows targets, the script prints the `.exe` artifact paths when the build
+finishes. Copy the generated files from `src/` and `src/qt/` to the Windows
+machine and run either `agrariand.exe` or `agrarian-qt.exe`.