Change npm install to npm ci for dependencies

Updated installation instructions for dependencies.

Author: netmindz

.github/copilot-instructions.md

@@ -8,7 +8,7 @@ Always reference these instructions first and fallback to search or bash command
 
 ### Initial Setup
 - Install Node.js 20+ (specified in `.nvmrc`): Check your version with `node --version`
-- Install dependencies: `npm install` (takes ~5 seconds)
+- Install dependencies: `npm ci` (takes ~5 seconds)
 - Install PlatformIO for hardware builds: `pip install -r requirements.txt` (takes ~60 seconds)
 
 ### Build and Test Workflow
@@ -135,4 +135,4 @@ The GitHub Actions workflow:
 4. Compiles firmware for multiple hardware targets
 5. Uploads build artifacts
 
-Match this workflow in your local development to ensure CI success.
+Match this workflow in your local development to ensure CI success.