Phase 6: town-crier news (website -> game)

BridgeTownCrier handles inbound towncrier.add / towncrier.remove, pushing
website-published news into GlobalTownCrierEntryList so every town crier
announces it until it expires. Both run on the Core thread (required: AddEntry
mutates a shared list and the criers send packets). An id maps to the created
TownCrierEntry so a later remove can pull it, and re-adding an id replaces the
prior entry.

Caps are enforced before touching the shared list -- line count, line length,
active-entry count, duration -- as defense in depth on top of the loopback trust
boundary: a buggy or compromised sidecar still cannot flood the criers or pin a
message forever. Config: Bridge.TownCrierMax{Lines,LineLength,Active,DurationSec}.

Verified with a sending stub and a probe that logs the actual crier list. Replies
and game state agree: add n1 -> towncrier.ok and the entry appears with the exact
lines; add n2 (8 lines over the cap of 6) -> towncrier.error and never enters the
list; remove n1 -> towncrier.ok and the entry is gone; remove unknown ->
towncrier.error. Evidence in docs/PLAN.md §16.

Adds BridgeJson.GetStringList for JSON string arrays, tools/stub_sidecar_crier.ps1,
and tools/scaffolding/BridgeCrierProbe.cs. This closes the pure-plugin inbound
work; only the PlayerVendorSale core edit (Phase 7) remains on the ServUO side.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

overlay/Scripts/Custom/Bridge/BridgeJson.cs

@@ -149,6 +149,35 @@ namespace Server.Custom.Bridge
             return v as string ?? Convert.ToString(v, CultureInfo.InvariantCulture);
         }
 
+        /// <summary>
+        ///     Extracts a JSON array of strings. JavaScriptSerializer materializes JSON arrays as
+        ///     object[] (or ArrayList) when the target is object, so handle both and stringify each
+        ///     element. Returns an empty list for a missing or non-array value, never null.
+        /// </summary>
+        public static List<string> GetStringList(Dictionary<string, object> o, string key)
+        {
+            var result = new List<string>();
+
+            object v;
+            if (o == null || !o.TryGetValue(key, out v) || v == null)
+                return result;
+
+            var enumerable = v as System.Collections.IEnumerable;
+
+            if (enumerable == null || v is string)
+                return result;
+
+            foreach (var item in enumerable)
+            {
+                if (item == null)
+                    continue;
+
+                result.Add(item as string ?? Convert.ToString(item, CultureInfo.InvariantCulture));
+            }
+
+            return result;
+        }
+
         public static int GetInt(Dictionary<string, object> o, string key, int fallback)
         {
             object v;