Insights: mentions monitoring + alternate analytics sources

[lbedner]

Summary

Expand the insights service with two new external data tracks:

1. Mentions monitoring — discover where the project is being talked about across the developer web (blog posts, forums, Q&A sites, social).
2. Alternate analytics sources — let Pulse pull docs traffic from GA4 in addition to Plausible, so users on either platform get the same dashboard.

The mentions feature alone would have surfaced the johnny233 CSDN article weeks earlier — that's the selling point.

Mentions monitoring — API reality

Platform	API	Auth	Notes
Google Alerts	No official API	RSS via google-alerts PyPI (cookie scrape)	Hacky but works. Set up alerts for keywords, poll the RSS feed.
Reddit	Official	OAuth2	Collector already exists. Search /r/all for keywords periodically.
Hacker News	Algolia search	None	https://hn.algolia.com/api/v1/search?query=<kw> — free, no auth.
Dev.to	Official	API key	Search articles endpoint.
Hashnode	GraphQL	None for public	Query posts by tag/keyword.
Stack Overflow	Official	API key (free)	Find questions mentioning the package.
GitHub	Already have	PAT	Cross-repo code/discussion/issue search.
X/Twitter	Official	OAuth2, paid tiers	Recent-tweet search.
Medium	No public search API	Scraping only	Skip for v1 — not reliable.
CSDN, Tencent Cloud, Juejin, Zhihu	No official API	Scraping required	Defer to v2 (Chinese platforms).

Priority for v1

1. Google Alerts RSS (covers most of what Google indexes, including CSDN articles).
2. Hacker News Algolia (one HTTP call, no auth).
3. Stack Overflow search.
4. GitHub cross-repo code/discussions search.
5. Reddit (extend existing collector with mentions search).

That gets ~80% of English-language mentions with minimal effort.

Alternate analytics — GA4 collector

GA4 has a real API: Google Analytics Data API v1beta, Python package google-analytics-data. Auth is a GCP service-account JSON.

Mapping to the metrics already displayed:

Pulse view	GA4 metric / dimension
Visitors	activeUsers
Pageviews	screenPageViews
Pages	pagePath
Countries	country
Sources	sessionSource
Avg duration	averageSessionDuration
Bounce rate	bounceRate

Setup is heavier than Plausible (GCP project + service account) but it's free and matches what most users already have. Pulse would treat it as a sibling collector — same insights tables, same dashboard, different source under the hood.

Acceptance criteria

• mentions collector(s) added behind feature toggles for each platform.
• New mentions insight surface in the Overseer (or Pulse) — list view + per-platform filter.
• GA4 collector implemented as an alternate to Plausible, configured via service-account JSON env var.
• Existing analytics dashboard renders correctly when GA4 is the source.
• Tests for each new collector with mocked API responses.

Out of scope

• Chinese platforms (CSDN, Juejin, Zhihu, Tencent Cloud) — v2.
• Medium scraping — not reliable enough.
• Sentiment analysis on mentions — v2.