docs: link CI experiment docs

[wochinge]

Summary\n- add a link from the README opener to the Langfuse docs for testing experiments in CI environments\n\n## Verification\n- pnpm exec prettier --check /tmp/experiment-action-docs-link-pr/README.md

[github-actions]

@claude review

[claude]

LGTM, simple docs link addition.

Extended reasoning...

Overview

This PR adds a single sentence to the README opener linking to the Langfuse docs page on testing experiments in CI environments. Only README.md is touched, and the change is purely additive prose with one external link.

Security risks

None. This is a docs-only change with no code, configuration, dependency, or workflow impact. The added URL points to the project's own documentation domain.

Level of scrutiny

Minimal. Documentation link additions are mechanical and low-risk; the link target is a Langfuse docs URL consistent with other docs links already in the README.

Other factors

The PR description notes prettier was run against the file, formatting is consistent with surrounding markdown, and no reviewer comments are outstanding.

[github-actions]

Experiment Results: b65fb73

Experiment	Status	Actions
Uppercase (py)	✅ Pass	View GitHub Action Run · View in Langfuse
Uppercase (ts)	✅ Pass	View GitHub Action Run · View in Langfuse
Mixed dir (node)	✅ Pass	View GitHub Action Run · View in Langfuse
Mixed dir (python)	✅ Pass	View GitHub Action Run · View in Langfuse
Regression fixture	❌ Regression	View GitHub Action Run · View in Langfuse

Details

✅ Uppercase (py) (Source)

Score	Value
avg_accuracy	1.000

Item results (3)

Item	Input	Expected	Output	exact_match
1	langfuse	LANGFUSE	LANGFUSE	1.000
2	world	WORLD	WORLD	1.000
3	hello	HELLO	HELLO	1.000

✅ Uppercase (ts) (Source)

Score	Value
avg_accuracy	1.000

Item results (3)

Item	Input	Expected	Output	exact_match
1	langfuse	LANGFUSE	LANGFUSE	1.000
2	world	WORLD	WORLD	1.000
3	hello	HELLO	HELLO	1.000

✅ Mixed dir (node) (Source)

Score	Value
avg_accuracy	1.000

Item results (3)

Item	Input	Expected	Output	exact_match
1	langfuse	LANGFUSE	LANGFUSE	1.000
2	world	WORLD	WORLD	1.000
3	hello	HELLO	HELLO	1.000

✅ Mixed dir (python) (Source)

Score	Value
avg_accuracy	1.000

Item results (3)

Item	Input	Expected	Output	exact_match
1	langfuse	LANGFUSE	LANGFUSE	1.000
2	world	WORLD	WORLD	1.000
3	hello	HELLO	HELLO	1.000

❌ Regression fixture (Source)

RegressionError: synthetic regression triggered by e2e fixture

Item results (3)

Item	Input	Expected	Output	exact_match
1	langfuse	LANGFUSE	LANGFUSE	1.000
2	world	WORLD	WORLD	1.000
3	hello	HELLO	HELLO	1.000