feat(tooltip): accurate per-pin data source attribution

Re-adds the 'Show data source' tooltip option (General tab, default off),
but accurate this time. The previous version was removed because it
guessed the source from the global data-source mode (showing Learner when
data was AscensionDB, etc.). This tags each pin with its real provenance
at creation and reads that tag.

- QuestieDB.GetPinDataSource(entityType, id, spawnData): resolves
  Learner (per-spawn isLearned or learner record), AscensionDB (curated
  ascensionOverrideKeys override), or base Questie DB. Never guesses.
- Objective pins tagged per-spawn in _DetermineIconsToDraw; available/
  finisher pins defaulted by quest in DrawWorldIcon; manual notes tagged
  Townsfolk in DrawManualIcon.
- World-map pins read the per-pin tag (MapIconTooltip); unit/object/item
  hovers derive per-id at the render layer (TooltipHandler via
  QuestieTooltips:GetDataSourceLine). Comms appended via KeyExists.
- No line shown when source is genuinely unknown (never misleading).

Modules/Options/QuestieOptionsDefaults.lua

@@ -87,6 +87,7 @@ function QuestieOptionsDefaults:Load()
             enableTooltipsObjectID = false,
             enableTooltipsQuestID = false,
             enableTooltipsQuestLevel = true,
+            enableTooltipsSource = false,
             showQuestXpAtMaxLevel = true,
             enableTooltipsNextInChain = true,
             learnerTooltips = true,