Document the News layer's own sources, keys and limits

DATA_SOURCES, the README's layer and key tables, CURRENT-STATE and the
changelog describe the News layer as it now is: a configured news server,
or Core's own reading of GDELT (no key), Liveuamap (optional) and World
News API (Local, free plan backlink credited). .env.example gives the
download sizes and the daily read budget; KNOWN-ISSUES lists what machine
coding gets wrong and which disputed areas are named as themselves.

docs/KNOWN-ISSUES.md

@@ -1,6 +1,6 @@
 # KNOWN ISSUES
 
-Updated: September 22, 2026
+Updated: November 5, 2026
 
 This file tracks active runtime issues only.
 
@@ -127,6 +127,26 @@ Status: Open (limits)
 
 ---
 
+### News layer without a news server
+Status: Open (limits)
+
+- GDELT's places and categories are machine-coded and approximate. A report can
+  be placed in the wrong town of the same name, or at a country an article only
+  names as a nationality ("Syrian refugees" placed in Syria).
+- Copies of one agency story are merged, but the same event under different
+  wording stays as separate reports.
+- Only the 11 disputed areas in the bundled list
+  (`src/data/local_data/natural_earth/README.md`) are named as themselves;
+  everywhere else Natural Earth's default country lines apply, so a place in
+  Western Sahara or Kashmir, for example, is named with the country those
+  lines put it in. GDELT places a whole city at one point: Jerusalem's falls
+  inside East Jerusalem, so it is named "Jerusalem" alone.
+- Local needs a World News API key. Its free plan allows 50 points a day; Core
+  stops at `WORLDNEWSAPI_DAILY_READS` reads (default 30) and Local then says the
+  daily limit is reached.
+
+---
+
 ## Closed / Intentional (for clarity)
 
 ### Proxy SSRF and error-surface hardening gaps