feat: support SavedVariablesPerCharacter for per-character addon data

Implement the SavedVariablesPerCharacter TOC directive that many addons
use to store different settings per character (Bartender, Dominos,
MoveAnything, WeakAuras, etc.). Without this, all characters share the
same addon data file.

Per-character files are stored as <AddonName>.<CharacterName>.lua.saved
alongside the existing account-wide <AddonName>.lua.saved files. The
character name is resolved from the player GUID at world entry time.

Changes:
- TocFile::getSavedVariablesPerCharacter() parses the TOC directive
- AddonManager loads/saves per-character vars alongside account-wide vars
- Character name set from game handler before addon loading

include/addons/addon_manager.hpp

@@ -26,6 +26,7 @@ public:
     bool isInitialized() const { return luaEngine_.isInitialized(); }
 
     void saveAllSavedVariables();
+    void setCharacterName(const std::string& name) { characterName_ = name; }
 
     /// Re-initialize the Lua VM and reload all addons (used by /reload).
     bool reload();
@@ -38,6 +39,8 @@ private:
 
     bool loadAddon(const TocFile& addon);
     std::string getSavedVariablesPath(const TocFile& addon) const;
+    std::string getSavedVariablesPerCharacterPath(const TocFile& addon) const;
+    std::string characterName_;
 };
 
 } // namespace wowee::addons

include/addons/toc_parser.hpp

@@ -18,6 +18,7 @@ struct TocFile {
     std::string getInterface() const;
     bool isLoadOnDemand() const;
     std::vector<std::string> getSavedVariables() const;
+    std::vector<std::string> getSavedVariablesPerCharacter() const;
 };
 
 std::optional<TocFile> parseTocFile(const std::string& tocPath);