docs: title the README with a logo banner that reads in every theme

[earakely-scale]

This puts the logo back at the top of the README, which is also the PyPI project page. It's a banner that reads in GitHub's light and dark themes alike, and on PyPI.

Why a banner

The README used to open with a <picture> that switched between a black-text and a white-text lockup on prefers-color-scheme. That media query follows the operating system, not GitHub's theme, so with GitHub set to dark and the OS set to light, visitors saw a black wordmark on a dark page. #30 replaced it with a text title.

This PR keeps the logo in a form that doesn't depend on the theme:

• The banner: assets/brand/readme-banner.png is cut from the social preview. It's the white-text lockup on its own dark card with rounded corners, so it looks the same on a light or a dark page.
• The title: the banner is the README's <h1>, with "AgentEnv Framework" as its alt text, so the name isn't repeated under the logo.
• The image URL: src is an absolute main URL, because PyPI can't resolve relative image paths. GitHub shows the banner once this merges.

Also

The opening paragraph's second sentence said "…speak the open agentenv-framework-protocol; it builds them…", which read as though the protocol builds and deploys environments. It now names AgentEnv Framework, as Greptile suggested on #30.

Verification

• I previewed the banner at README width on GitHub's light (#ffffff) and dark (#0d1117) page backgrounds, and it reads on both.
• twine check --strict passes on the built wheel and sdist, so PyPI's renderer accepts the markup.
• tst/unit/test_check_plugin_api.py, which parses the README, passes.

bump-version is set so the banner reaches PyPI.

🤖 Generated with Claude Code

Confidence Score: 4/5

The PR appears safe to merge, though older PyPI pages could lose or change their banner later.

Findings

1.  Older banners can change ▶

Fix with agent prompt

### Issue 1
README.md:1
The banner URL points to `main`, even when the README is published for a release tag. If someone later replaces or removes that file on `main`, visitors to an older PyPI release will see the wrong banner or a broken image. Point the image at a fixed revision so each release keeps its banner.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Summary

The README now opens with a logo banner, which also appears on the PyPI project page. Its opening description names AgentEnv Framework as the builder and deployer of environments.

• The banner serves as the README title and uses an absolute image URL.
• The introduction names AgentEnv Framework explicitly.

_{Reviews (1) · Last reviewed commit: "docs: name AgentEnv Framework, not the p..."}

[greptile-apps]

Older banners can change

The banner URL points to main, even when the README is published for a release tag. If someone later replaces or removes that file on main, visitors to an older PyPI release will see the wrong banner or a broken image. Point the image at a fixed revision so each release keeps its banner.

Prompt To Fix With AI

This is a comment left during a code review.
Path: README.md
Line: 1

Comment:
**Older banners can change**

The banner URL points to `main`, even when the README is published for a release tag. If someone later replaces or removes that file on `main`, visitors to an older PyPI release will see the wrong banner or a broken image. Point the image at a fixed revision so each release keeps its banner.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

[earakely-scale]

Keeping main on purpose. The release tag doesn't exist when the README is written, and this PR's commit SHA gets replaced when it's squash-merged, so neither gives a stable URL at authoring time. The previous lockup used main URLs too. The banner is a brand asset under assets/brand/, and anyone who renames it should keep the old path.

[greptile-apps]

That context makes sense. Given the banner is a stable, backward-compatible brand asset, the release tag is unavailable when the README is authored, and squash-merging invalidates the pre-merge commit SHA, keeping the main URL is the practical choice. I’m withdrawing this finding; no change is needed.