Add Google ADK AI observability installation page

[marco-g-pm]

Changes

• Adds the Google ADK page to the AI observability installation docs. It imports the shared onboarding content that landed in PostHog/posthog#92781, documenting the PostHogADKPlugin adapter released in @posthog/ai 8.10.0 (PostHog/posthog-js#4687).
• Adds the "Google ADK" entry to the installation nav (Gemini icon). The installation index grid picks the page up from its frontmatter.

The page rendered correctly on a local Gatsby build against the merged onboarding content: steps, code blocks, step TOC, and nav entry.

Checklist

• I've read the docs and/or content style guides.
• Words are spelled using American English
• Use relative URLs for internal links
• I've checked the pages added or changed in the Vercel preview build
• If I moved a page, I added a redirect in vercel.json (no page moved)

🤖 Generated with Claude Code

[github-actions]

Deploy preview

Status	Details	Updated (UTC)
🟢 Ready	View preview	Sep 03, 2026 03:13PM

[github-actions]

Bundle report

Total JS (gzip)

8.16 MiB (+3.4 KiB / +0.0%)

Largest changed named chunks

Chunk	Gzip	Δ vs master
app.js	2294.8 KiB	+3.4 KiB / +0.1%

Eager graph (modules shipped in each entrypoint's initial chunks)

Entrypoint	Eager size	Budget	Modules
✅ app	18.40 MiB (+12.5 KiB / +0.1%)	report-only	2051

Largest modules in the app closure

Module	Size
./src/data/mcp-tools.json	1073.6 KiB
css ./node_modules/.pnpm/css-loader@5.2.7_webpack@5.101.3/node_modules/css-loader/dist/cjs.js??ruleSet[1].rules[8].oneOf[1].use[1]!./node_modules/.pnpm/postcss-loader@4.3.0_postcss@8.5.6_webpack@5.101.3/node_modules/postcss-loader/dist/cjs.js??ruleSet[1].rules[8].oneOf[1].use[2]!./src/styles/global.css	758.3 KiB
./src/components/Stickers/Stickers.tsx	696.4 KiB
./node_modules/.pnpm/@radix-ui+react-icons@1.3.2_react@18.3.1/node_modules/@radix-ui/react-icons/dist/react-icons.esm.js	481.4 KiB
./node_modules/.pnpm/@posthog+brand@0.8.0_react@18.3.1/node_modules/@posthog/brand/dist/generated/hoggies/svg/x-ray.mjs	480.8 KiB
./node_modules/.pnpm/rehype-raw@7.0.0/node_modules/rehype-raw/lib/index.js + 29 modules	395.1 KiB
./node_modules/.pnpm/@posthog+brand@0.8.0_react@18.3.1/node_modules/@posthog/brand/dist/generated/hoggies/svg/im-the-driver.mjs	385.7 KiB
./src/hooks/useCustomers.tsx + 55 modules	370.0 KiB
./node_modules/.pnpm/@posthog+icons@0.36.6_react-dom@18.3.1_react@18.3.1__react@18.3.1/node_modules/@posthog/icons/dist/posthog-icons.es.js	354.8 KiB
./node_modules/.pnpm/react-markdown@8.0.7_@types+react@16.14.66_react@18.3.1/node_modules/react-markdown/lib/react-markdown.js + 88 modules	351.4 KiB
./src/components/ProductComparisonTable/index.tsx + 126 modules	301.7 KiB
./node_modules/.pnpm/cloudinary-core@2.14.0_lodash@4.17.21/node_modules/cloudinary-core/cloudinary-core.js	281.9 KiB
./node_modules/.pnpm/@posthog+brand@0.8.0_react@18.3.1/node_modules/@posthog/brand/dist/generated/hoggies/svg/doll-house.mjs	281.7 KiB
./node_modules/.pnpm/@posthog+brand@0.8.0_react@18.3.1/node_modules/@posthog/brand/dist/generated/hoggies/svg/director.mjs	275.6 KiB
./src/components/SearchUI/index.tsx + 87 modules	273.0 KiB

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Eager-graph budgets are report-only until a baseline is established. Sizes are gzip of public/**/*.js; eager size is webpack module source bytes for the modules actually shipped in the entrypoint's initial chunks (post-tree-shake).