connectors: add google-analytics-4 (Admin + Data + Realtime + Funnel)

[keysersoft]

Summary

New `google-analytics-4` adapter mirroring the 7 tools the upstream googleanalytics/google-analytics-mcp server exposes. Catalog grows 167 → 168.

Tool	Endpoint
`ga4_get_account_summaries`	Admin v1beta `/accountSummaries`
`ga4_get_property_details`	Admin v1beta `/properties/{id}`
`ga4_list_google_ads_links`	Admin v1beta `/properties/{id}/googleAdsLinks`
`ga4_list_custom_dimensions`	Admin v1beta `/properties/{id}/customDimensions`
`ga4_list_custom_metrics`	Admin v1beta `/properties/{id}/customMetrics`
`ga4_run_report`	Data v1beta `/properties/{id}:runReport`
`ga4_run_realtime_report`	Data v1beta `/properties/{id}:runRealtimeReport`
`ga4_run_funnel_report`	Data v1alpha `/properties/{id}:runFunnelReport`

Single adapter, dual host (analyticsadmin + analyticsdata) via the absolute-URL support already in the REST engine.

Auth

User OAuth2 with refresh token against `oauth2.googleapis.com/token`. Already supported by the engine — same flow as Zoho/Pinterest/FreshBooks/Sage.

Service account JWT (RS256) intentionally not supported in v1 — would require new engine code (~1-2 days). Documented in the connector `instructions` with a workaround (dedicated automation Google account). I'll add RS256 to the engine when there's enough demand to justify it; that work unlocks Drive/Sheets/BigQuery/Calendar too.

Vendor-MCP-already-exists situation

Yes — Google ships an official Python MCP server. Same value-add reasoning as our HubSpot / Atlassian audit (PR #232 era):

Their MCP	AnythingMCP wrapper
Local `pipx run analytics-mcp` install	Zero install, browser-based
gcloud ADC JSON file on disk	Encrypted refresh_token in our DB
Per-machine config	One MCP key across Claude + ChatGPT + Copilot
No audit log	Per-tool-call audit log for governance

Verification

```
$ node scripts/validate-adapters.mjs
Validated 168 adapters: 168 passed, 0 failed.

$ npx jest --testPathPatterns='google-analytics-4|catalog.spec' --silent
Test Suites: 2 passed
Tests: 2143 passed, 2143 total
```

Live spec asserts:

• baseUrl = analyticsadmin (Admin host)
• OAuth2 against `oauth2.googleapis.com/token`
• All 3 report tools route to `analyticsdata.googleapis.com` (absolute URLs)
• All 5 admin tools route to `analyticsadmin.googleapis.com`
• Full tool naming + cardinality

Test plan

• CI green
• Merge → trigger docker-publish.yml → deploy-cloud.yml
• Verify `curl https://cloud.anythingmcp.com/api/adapters | jq 'map(select(.slug=="google-analytics-4"))'` returns 1 entry
• After deploy: follow-up PR on website repo for the EN/DE/IT/ES/JA/RU/ZH guides (auto-generated)