docs: Sign in with Google auth recipe

[amsraman]

Adds a "Sign in with Google" page under docs/authentication/ (which currently only has the overview). Covers the reflex-google-auth package: GoogleAuthState, token_is_valid/tokeninfo, the require_google_login decorator, and google_login() inside google_oauth_provider.

Draft — from the AI-builder memory corpus. Draft pending a news fragment / skip-changelog label and a sidebar entry if the auth section needs one.

🤖 Generated with Claude Code

[codspeed-hq]

Merging this PR will not alter performance

✅ 26 untouched benchmarks
⏩ 8 skipped benchmarks¹

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_{Comparing docs/google-auth-recipe (5b81c0d) with main (7e80931)}

Footnotes

1. 8 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[greptile-apps]

Greptile Summary

Adds a new "Sign in with Google" recipe page under docs/authentication/ and wires it into the sidebar. The page covers installation, environment variable setup, state subclassing with GoogleAuthState, the require_google_login decorator, the google_login()/google_oauth_provider pattern, and an API reference stub.

• The sidebar entry (authentication.google) is correctly added; the dynamic markdown-discovery pipeline resolves it to the new google.md file automatically.
• The API reference stub block is missing from typing import Callable, TypedDict, leaving the block non-self-contained for readers who copy it.

Confidence Score: 5/5

Documentation-only change with no runtime impact; safe to merge.

Both changed files are pure documentation — a new Markdown recipe page and a one-line sidebar addition. No application logic, state management, or security-sensitive code is touched.

The API reference code block in docs/authentication/google.md is missing TypedDict and Callable imports, making it non-self-contained, but this has no runtime consequences.

Important Files Changed

Filename	Overview
docs/authentication/google.md	New recipe page covering installation, environment variables, state subclassing, the login button, and an API reference stub; the API reference block omits TypedDict and Callable imports, making the stubs non-self-contained.
docs/app/reflex_docs/templates/docpage/sidebar/sidebar_items/learn.py	Adds authentication.google to the Authentication sidebar section; the dynamic markdown-discovery pipeline will resolve this to the new google.md file automatically.

_{Reviews (2): Last reviewed commit: "docs: add Sign in with Google page to Au..." | Re-trigger Greptile}

[greptile-apps]

Sidebar entry not added for the new page

docs/app/reflex_docs/templates/docpage/sidebar/sidebar_items/learn.py hard-codes the Authentication section with only authentication.authentication_overview. The new google.md page will be accessible by direct URL (the docgen pipeline auto-discovers all .md files) but will not appear in the sidebar navigation. The PR description flags this as a pending TODO, but it blocks discoverability — the page is unreachable for users browsing the docs.

[amsraman]

Fixed. Added authentication.google to the Authentication section's children in learn.py so the page appears in the sidebar nav (naming matches the auto-discovered module, same convention as authentication.authentication_overview).