docs: add app icon and demo image to readme

[jacobjmc]

Adds the app icon and demo screenshot to the README so the repo landing page has a clearer visual introduction.

---

Summary by cubic

Add a centered app icon and a demo screenshot to the README to give visitors a quick visual of OpenCode Monitor.
Includes the new OpenCodeMonitorDemo.png asset and references public/app-icon.png.

^{Written for commit 27c32e2. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 1 file

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="README.md">

<violation number="1" location="README.md:2">
P2: README references `public/app-icon.png`, but that file is not present in the repository, so the icon will not render.</violation>

<violation number="2" location="README.md:13">
P2: README references `OpenCodeMonitorDemo.png`, but no matching file exists, so the demo screenshot link is broken.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: README references OpenCodeMonitorDemo.png, but no matching file exists, so the demo screenshot link is broken.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At README.md, line 13:

<comment>README references `OpenCodeMonitorDemo.png`, but no matching file exists, so the demo screenshot link is broken.</comment>

<file context>
@@ -6,6 +10,8 @@ It is forked from [CodexMonitor](https://github.com/Dimillian/CodexMonitor) by D
 
 OpenCode Monitor is an independent community project and is not affiliated with or endorsed by the OpenCode team.
 
+![OpenCode Monitor demo](OpenCodeMonitorDemo.png)
+
 ## Status
</file context>

[cubic-dev-ai]

P2: README references public/app-icon.png, but that file is not present in the repository, so the icon will not render.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At README.md, line 2:

<comment>README references `public/app-icon.png`, but that file is not present in the repository, so the icon will not render.</comment>

<file context>
@@ -1,3 +1,7 @@
+<p align="center">
+  <img src="public/app-icon.png" alt="OpenCode Monitor icon" width="128" height="128">
+</p>
+
</file context>