docs: update installation instructions

README.md

@@ -37,11 +37,36 @@ The `ffca-architecture` skill defers to `layered-architecture` when it sees the
 
 ## Installation
 
-The plugin is published in the [Very Good Claude Marketplace](https://github.com/VeryGoodOpenSource/very-good-claude-code-marketplace). Inside Claude:
+One-line install from your terminal:
 
 ```bash
-/plugin marketplace add VeryGoodOpenSource/very-good-claude-code-marketplace
-/plugin install vgv-ffca-plugin
+claude plugin marketplace add VeryGoodOpenSource/very-good-claude-code-marketplace && claude plugin install vgv-ffca-plugin
+```
+
+Or inside an active Claude Code session, run these as **two separate commands** (the second only after the first completes):
+
+1. Add the marketplace:
+
+   ```text
+   /plugin marketplace add VeryGoodOpenSource/very-good-claude-code-marketplace
+   ```
+
+2. Install the plugin:
+
+   ```text
+   /plugin install vgv-ffca-plugin
+   ```
+
+For more details, see the [Very Good Claude Marketplace](https://github.com/VeryGoodOpenSource/very-good-claude-code-marketplace).
+
+### Local development
+
+Load the plugin from a local checkout, validate it, and run the validator tests:
+
+```bash
+claude --plugin-dir .
+claude plugin validate .
+cd scripts && dart test
 ```
 
 ## Skills