fix(tracker): show (Complete) and correct level for DB-less custom quests

Quests with no static DB entry (e.g. Ascension custom quest 175206) made
GetColoredQuestName bail out early on a nil name lookup, before it ever
reached the (Complete)/(Failed) suffix logic. The tracker's existing
fallback for that case never added the suffix either, and it computed
level via QuestieLib.GetTbcLevel (static-DB-only), which silently defaults
to level 1 and then gets scaled from that wrong base by Ascension's level
scaling. Since these quests also auto-collapse once complete (hiding the
tracker's other "Quest Complete!" indicator line), the title was the only
place that could show completion status, and it was silently swallowing it.

- QuestieTracker.lua: the "no DB name" fallback branch now appends
  (Complete) under the same collapseCompletedQuests/isMinimizable rule as
  the normal path, and uses the live quest object's own level instead of
  the static-only lookup.
- QuestieQuest.lua (PopulateQuestLogInfo): re-syncs quest.level from a live
  GetQuestLogTitle scan every update, since QuestieDB.GetQuest caches quest
  objects permanently and QuestLogCache never tracked level at all.
- TrackerUtils.lua (GetCompletionText): guards the Description[1] fallback
  against quests that have no top-level Description array, which was
  throwing and aborting that quest's tracker render entirely.

Modules/Tracker/TrackerUtils.lua

@@ -379,8 +379,14 @@ function TrackerUtils:GetCompletionText(quest)
 
     if completionText then
         return completionText
-    else
+    elseif quest.Description and quest.Description[1] then
         return quest.Description[1]:gsub("%.", "")
+    else
+        -- Fallback/custom quests (e.g. server quests not in QuestieDB) have no
+        -- top-level Description array. Without this, indexing quest.Description[1]
+        -- throws and aborts the whole tracker render for that quest via the
+        -- caller's pcall, freezing its line on the last successful render.
+        return nil
     end
 end