refac: migration crash, real-database tests, site deleted during create, ruels out of the repo, lists

docs/performance.md

@@ -12,3 +12,7 @@
 | default page, no `?seo=` | 307 to 329 ms |
 
 The target is 300 ms for 5,000 articles. Both requests sit slightly above it on the development machine, so the test logs the target but only fails above 500 ms; no cache or index was added. Re-run it with `go test -tags nofrontend ./test/... -run TestSeoFilterPerformance -v -count=1` after a change to the assessment rules or the article repository.
+
+## The `?seo=` filter of the grouped list
+
+`GET /v1/article/?group=story` uses the same assessment. The versions whose status matches (and, with `q`, whose title matches: the title search runs once per request through `article.Repository.FindTitleMatches`) are handed to the repository as `StoryFilters.VersionIDs`. That set can be larger than any bind-parameter limit (SQLite accepts 32,766 parameters), so it never becomes an `IN (?, …)` list: the repository reads the qualifying `(story_id, id)` pairs and the ordered story rows with id-only projections and keeps the members of the set in memory before paging. `ListByStories` reads the versions of the page without their bodies and only those the caller may read; the representative's body comes from the assessment pass, which still reads every visible body because the status depends on it. `TestArticleStoryListSEOFilterAtScaleSQLite` covers 40,001 versions.