feat: add Arknights: Endfield, and stop passing off requirements as summaries

Endfield was previously written off as undatable. That was wrong: a first
pass only inspected its Duration rows (all "Permanently Available") and its
year-less version grid, and missed an "Event | Schedule & Summary" table
whose cells read "Period: 08/09/26 - 08/30/26 During the event...". Two real
events, with a year.

Adds MM/DD/YY range parsing for that shape. Month-first ordering is not
assumed lightly — Endfield's own version grid reads 01/22, 04/17, 07/16 for
versions 1.0, 1.2 and 1.4, chronological only if the month comes first.

Also stops presenting unlock conditions as descriptions. Several templates
put "Reach Union Level 8" where a blurb would go; filling the summary slot
with text that never says what the event is is worse than leaving it empty.
Wuthering Waves correctly drops to zero summaries as a result.

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

docs/INGESTION.md

@@ -94,10 +94,13 @@ Game8 uses at least three page templates and a game's page may use any of them:
 2. **Column tables** — `Event | Duration | Event Details | Rewards`, one row per event, under a
    section heading. *(Neverness to Everness)*
 3. **Image-grid schedules** — a bare `MM/DD`, no year, no end date. **Unsupportable.**
-   *(Arknights: Endfield)*
+4. **Combined cells** — one cell holding label, range and blurb
+   (`Period: 08/09/26 - 08/30/26 During the event...`). *(Arknights: Endfield)*
 
-Shapes 1 and 2 are handled. Before assuming a new Game8 page will work, dump its heading/table
-structure and check which shape it uses.
+Shapes 1, 2 and 4 are handled. Before assuming a new Game8 page will work, dump its heading/table
+structure and check which shape it uses — and check **every** table, not just the obvious one.
+Endfield was written off as undatable on a first pass that only inspected its `Duration` rows; its
+two real events were in a table further down.
 
 ## Stage 1 — fetch