fix: nws area truncation — configurable word-boundary cap (default 80)

Replace hardcoded 50-char area cap with adapter_config key
nws.area_max_chars (default 80). Truncation now appends ellipsis when
cut, matching the locations_max_chars pattern from the prior commit.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

meshai/adapter_config/defaults.py

@@ -576,6 +576,11 @@ REGISTRY: dict[tuple[str, str], dict[str, Any]] = {
         "type": "int",
         "description": "Maximum characters for the locations field on line 4 of NWS wire. Truncates at word boundary.",
     },
+    ("nws", "area_max_chars"): {
+        "default": 80,
+        "type": "int",
+        "description": "Maximum characters for the area field on line 2 of NWS wire. Truncates at last word boundary.",
+    },
 
     # =================================================================
     # AVALANCHE -- 1 setting (min danger level broadcast floor)

meshai/central/nws_handler.py

@@ -324,8 +324,12 @@ def _render(*, event_type, area_desc, geocoder_city, county, state,
     else:
         time_seg = ""
     area = (area_desc or "").split(";")[0].strip()
-    if len(area) > 50:
-        area = area[:50].rsplit(" ", 1)[0]
+    _area_limit = int(adapter_config.nws.area_max_chars)
+    if len(area) > _area_limit:
+        cut = area[:_area_limit].rsplit(" ", 1)[0]
+        if not cut:
+            cut = area[:_area_limit]
+        area = cut + "\u2026"
     if time_seg and area:
         line2 = f"{time_seg} — {area}"
     elif time_seg: