fix(docs): preserve PyPI hero image aspect ratio

[hassiebp]

What changed

Replace the README hero's fixed-size HTML img element with standard Markdown image syntax.

Why

PyPI constrains project-description images to the content column with max-width: 100%, but the explicit height="600" remained fixed when the declared 2400 px width was reduced. The current listing therefore renders the 4:1 source image with a distorted aspect ratio.

Using dimension-free Markdown lets the renderer derive height from the image's intrinsic 2400×600 dimensions while keeping it responsive on GitHub and PyPI.

Fixes LFE-15269.

Impact

The Langfuse PyPI listing will show the README hero at its intended aspect ratio after the next package release.

Verification

• git diff --check
• uv build --out-dir /tmp/lfe-15269-pr-dist --no-sources
• twine check /tmp/lfe-15269-pr-dist/*
• Inspected the wheel METADATA to confirm the dimension-free Markdown image is included in the published description

Greptile Summary

The PR replaces the fixed-dimension HTML hero image with standard Markdown image syntax so renderers can preserve its intrinsic aspect ratio.

• Keeps the existing image URL.
• Adds descriptive alternative text.
• Removes explicit width and height attributes that distorted the image on PyPI.

Confidence Score: 5/5

The PR appears safe to merge with no blocking or non-blocking issues identified.

The standard Markdown image syntax is already used elsewhere in the README, preserves the existing asset URL, and is compatible with the README’s package-description role.

_{Reviews (1): Last reviewed commit: "fix(docs): preserve PyPI hero image aspe..." | Re-trigger Greptile}

[github-actions]

@claude review

[claude]

LGTM — simple, self-contained README fix that swaps a fixed-size HTML img tag for dimension-free Markdown to preserve the image's aspect ratio on PyPI.

What was reviewed: confirmed the change is scoped to a single line in README.md, verified the Markdown syntax is correct and the image URL/alt text are preserved, and checked no other references to the old HTML img tag exist elsewhere in the repo.

Extended reasoning...

Overview

The PR changes a single line in README.md, replacing a fixed-width/height HTML <img> tag with standard Markdown image syntax ([alt](url)). The motivation is that PyPI's rendering constrains the image to max-width: 100% but keeps the explicit height="600", distorting the aspect ratio; dimension-free Markdown lets the renderer derive height from the intrinsic image dimensions.

Security risks

None. This is a documentation-only change to a README file — no code, dependencies, or configuration affecting the SDK's behavior are touched. The image URL is unchanged (same GitHub user-attachments asset), so there's no new external resource being introduced.

Level of scrutiny

Minimal scrutiny is warranted. This is a mechanical, cosmetic docs fix with no logic changes, no CODEOWNER-sensitive paths, and no test coverage implications. The author's verification steps (build check, twine check, inspecting wheel METADATA) are more than sufficient for a change of this scope.

Other factors

Grepped the repo and confirmed no other files reference the old HTML img tag for this hero image, so there's no inconsistency introduced. No outstanding review comments in the PR timeline to address.