feat: add Zenith strategy and move latency tracing

- Register Zenith 1.1 with balanced duel verdicts and forced-outcome overrides.
- Prioritize permanent-trail space in Constrictor and health-aware hazard routes.
- Deduct executor queue delays and return fallback directions on move timeouts.
- Correlate response headers, replay timings, and sampled structured trace logs.
- Move shared metrics publication off the response path without losing local counts.
- Allow configurable tournament opponents and add a psql helper recipe.
- Preserve empty latency values through compact replay encoding and migration.
- Update Arena game links and use default assets for missing customizations.
- Cover strategy, HTTP lifecycle, tracing, replay codecs, and dashboard behavior.
- Validate with 260 passing Python tests, 4 skips, and 2 passing JavaScript tests.

server/database/compact/codec.py

@@ -27,17 +27,24 @@ def decode_move(code:int|None) -> str|None:
     return None
   return MOVES[int(code) - 1]
 
+# The engine reports latency as a string; "" means no response was measured.
+_EMPTY_LATENCY = -32768
+
 def encode_latency(latency:object) -> int|None:
-  if latency is None or latency == "":
+  if latency is None:
     return None
+  if latency == "":
+    return _EMPTY_LATENCY
   try:
     value = int(str(latency))
   except ValueError:
     return None
-  return value if -32768 <= value <= 32767 else None
+  return value if _EMPTY_LATENCY < value <= 32767 else None
 
 def decode_latency(value:int|None) -> str|None:
-  return None if value is None else str(value)
+  if value is None:
+    return None
+  return "" if value == _EMPTY_LATENCY else str(value)
 
 def _point(point:object) -> tuple[int, int]|None:
   if not isinstance(point, dict):