docs: add store/source install + dev instructions, pin Node 26

.node-version

@@ -0,0 +1 @@
+26

README.md

@@ -18,55 +18,102 @@ This project aims to be a simple and easy to use DDC brightness control plugin f
 - Support for direct i2c or better ddc controllers (not ddcutil)
 - You tell me
 
-## Installation
+## Requirements
 
-(Examples use arch, but all packages should be available on other distros as well)
-
-Be sure to have [ddcutil](https://www.ddcutil.com/) installed it is a hard requirement for now
-
-Also, if installing from source install just which is the chosen command runner for this project
+Regardless of how you install the extension, it shells out to
+[ddcutil](https://www.ddcutil.com/) to talk to your monitors, so it is a hard
+requirement.
 
 ```bash
-sudo pacman -Syu ddcutil just
+sudo pacman -S ddcutil
 ```
 
-Add your user to the i2c group so it can use i2c without root and reboot/login+out
+Then add your user to the `i2c` group so `ddcutil` can talk to the bus without
+root, and re-login (or reboot):
 
-```bash 
+```bash
 sudo usermod -aG i2c $USER
 reboot
 ```
 
-Now install the extension from version control
-(until we get to the gnome extension store)
+## Installation
 
-```bash 
+Pick whichever method fits you. All three install the same extension — the
+store and manager routes are the easiest, building from source gives you the
+latest commits.
+
+### 1. GNOME Extensions Website (easiest)
+
+Head to the listing and click **Install**:
+
+<https://extensions.gnome.org/extension/10312/ddc-brightness-controller/>
+
+Clicking Install opens the browser connector. If prompted, install the
+"Shell Extension Manager" browser extension for your browser, approve the
+connection, and the extension installs straight into your running session.
+
+### 2. GNOME Extensions Manager App
+
+Search for **"DDC Brightness Controller"** in the
+[Extensions](https://flathub.org/apps/details/com.mattjakeman.GNOME.Extensions)
+app (from Flathub) and hit install. On X11 the same app also lets you install
+directly from the website link above.
+
+### 3. From Source (git clone)
+
+Builds the extension locally and drops it into your user's extension dir.
+Requires [just](https://github.com/casey/just) as the command runner.
+
+Arch Linux:
+
+```bash
+sudo pacman -S git just
+```
+
+Clone and install:
+
+```bash
 git clone https://github.com/lucasoskorep/ddc-brightness-control
 cd ddc-brightness-control
 just install
 ```
 
+After installing from source, enable it (toggle in the Extensions app, or):
+
+```bash
+gnome-extensions enable ddcbrightness@lucaso.io
+```
+
+Re-login or restart the shell (`Alt+F2` → `r` on X11) to pick it up.
+
 ## Development
 
-You need a couple of other things for development ideally
+Building and debugging locally needs a few extra tools beyond the runtime
+requirements above:
 
-- uv
-- fnm
+- `just` — the command runner
+- `fnm` — fast node version manager (the build runs on Node via pnpm)
+- `uv` — python package manager (used by the schema-analysis helper)
+- `glib2` — provides `glib-compile-schemas` for compiling the settings schema
+
+Arch Linux:
 
-### Installation
 ```bash
-just install
+sudo pacman -S just fnm uv glib2
 ```
 
-### Linting
+Set up the Node runtime with fnm (the pinned version lives in `.node-version`):
+
 ```bash
-just lint
-just lint-fix #(auto fixes what it can via eslint)
+fnm install
+fnm use
 ```
 
-### Debugging
+Then:
+
 ```bash
-just live-debug
+just install      # install deps + build + drop into the extension dir
+just lint         # lint
+just lint-fix     # auto-fix what eslint can
+just live-debug   # tail gnome-shell logs while you poke at it
 ```
-
-