fix: move @max_indexes before first use to fix type comparison warning

Module attribute was defined after its use in handle_call, causing
Elixir to compare map_size against nil. lith-http now compiles with
0 warnings.

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

Author: hyperpolymath

lithoglyph/lith-http/lib/lith_http/temporal_index.ex

@@ -20,6 +20,10 @@ defmodule LithHttp.TemporalIndex do
 
   @table_prefix :temporal_index_
 
+  # Maximum number of temporal indexes to prevent atom table exhaustion.
+  # Each index creates one atom for the ETS named table.
+  @max_indexes 10_000
+
   # Client API
 
   def start_link(_opts) do
@@ -212,10 +216,6 @@ defmodule LithHttp.TemporalIndex do
     end
   end
 
-  # Maximum number of temporal indexes to prevent atom table exhaustion.
-  # Each index creates one atom for the ETS named table.
-  @max_indexes 10_000
-
   # Private functions
 
   @doc false