Record the Honkai Impact 3rd source and what its dates are worth

SOURCES.md § 13 declined this game's only known source partly because every
boundary was a week bucket, and we have now built a different source with that
same objection standing. Leaving that contradiction unwritten is how a later
pass rediscovers the trade the expensive way, so § 14 records the decision
itself: the conduct evidence, which three of § 13's four objections arustats
answers, which one it does not, and that any source stating a date per event
retires it. § 13 is marked superseded rather than rewritten — its verdict on
marisaimpact.com still stands and was not re-tested.

AGENTS.md gets the same warning where a parser author will hit it, because the
estimate is not visible from the code: the numbers look like every other
day-precision date in the project.

Also corrects the counts this game made false — nine parsers, twenty sources,
nineteen games. The "stopped working at eighteen" passages are left alone: they
date the settings-panel redesign, and bumping them would falsify the history
rather than update a count.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

docs/INGESTION.md

@@ -56,11 +56,18 @@ Consequences worth internalising:
 | `holodoriwiki` | holodori.wiki's rendered `/wiki/Events` — `Current Events` and `Past Events` wikitables over `Event \| Type \| Start Date \| End Date` | hololive Dreams |
 | `iopwiki` | iopwiki.com's `gf-table event-period` tables — `Title \| Period (start/end) \| Server \| Type \| Comment`, one table per event and one row per server | Girls' Frontline 2 |
 | `stellasorawiki` | stellasora.miraheze.org's front-page `Current Banners` module — `<time datetime>` pairs inside `stellasora-home-banner` blocks | Stella Sora |
+| `arustats` | arustats.com's Next.js `__NEXT_DATA__` blob — a per-version week grid, with events carrying `startWeek`/`endWeek` **integers** rather than dates. **Estimated boundaries** — see AGENTS.md § Honkai Impact 3rd | Honkai Impact 3rd |
 
 `wikigg` is the better shape by a distance: it emits ISO timestamps with one timer per server
 region, so its events carry exact precision and real `regionEnds`. Prefer a source like that over a
 prose wiki when both exist, and give it a higher `priority`.
 
+`arustats` is the outlier on precision rather than on markup, and it is the only source in the
+project that does not publish a date per event: its page schedules by week bucket and labels the grid
+`ESTIMATED WEEK`, so every boundary it emits is an estimate. It carries `confidence: 0.4` for that
+reason, against the 0.85–0.95 everything else earns, which is also what makes `mergeEvents` prefer
+any real source that replaces it. Read AGENTS.md § Honkai Impact 3rd before changing it.
+
 `fandom` is the only parser whose body is not HTML: it reads an `action=parse` JSON envelope and
 takes the rendered wikitext out of `parse.text`. That is not a preference — the rendered page is
 behind a Cloudflare challenge and the API is the surface the wiki's `robots.txt` allows, so the