docs(readme): left-align install code blocks (were centered by the hero div)

The `<div align="center">` hero centered each line of the code blocks, so shorter
lines (`cd your-project`, `npm i -g …`) rendered with stray leading indentation.
Close the centered hero after the badges; install/init sections render normally.
Only the screenshot stays centered.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -19,9 +19,9 @@
 [![Codex CLI](https://img.shields.io/badge/Codex_CLI-supported-blueviolet.svg)](#)
 [![opencode](https://img.shields.io/badge/opencode-supported-blueviolet.svg)](#)
 
-<br />
+</div>
 
-### Get Started
+## Get Started
 
 **No Node.js required** — one command grabs the right build for your OS:
 
@@ -40,15 +40,17 @@ npx @colbymchenry/codegraph        # zero-install, or:
 npm i -g @colbymchenry/codegraph
 ```
 
-<sub>CodeGraph bundles its own runtime — nothing to compile, no native build, works the same everywhere.<br />The interactive installer auto-configures your agent(s) — Claude Code, Cursor, Codex CLI, opencode.</sub>
+<sub>CodeGraph bundles its own runtime — nothing to compile, no native build, works the same everywhere. The interactive installer auto-configures your agent(s) — Claude Code, Cursor, Codex CLI, opencode.</sub>
 
-#### Initialize Projects
+### Initialize Projects
 
 ```bash
 cd your-project
 codegraph init -i
 ```
 
+<div align="center">
+
 ![1_C_VYnhpys0UHrOuOgpgoyw](https://github.com/user-attachments/assets/f168182f-4d9a-44e0-94d7-08d018cc8a3a)
 
 </div>