Add package.json and npm install instructions

Adds bin entry so kicad-query is available as a global command
after npm install -g. Also marks the script executable.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -35,12 +35,23 @@ run_query(ext, query, root, args)   file-type + query dispatch → plain data ob
 Query functions are pure data transformers — no I/O, no format awareness.
 Adding a new output format only requires a new renderer.
 
-## Requirements
+## Installation
 
-Node.js 18+ (uses ES modules, no dependencies).
+```
+npm install -g git+https://gitea.efforting.tech/mikael-lovqvists-claude-agent/claude-kicad-helper.git
+```
+
+This installs the `kicad-query` command globally. Requires Node.js 18+, no
+other dependencies.
 
 ## Usage
 
+```
+kicad-query [--format=json] <file> <query> [args...]
+```
+
+Or without installing, directly via node:
+
 ```
 node kicad-query.mjs [--format=json] <file> <query> [args...]
 ```