Art tooltips: "Verbessert durch" lists what improves each art

Arts are objects (game::Art) built from the game's definitions: name,
launch type, damage source, regeneration group and the skills' art lists.
The tooltip gets one line per effect of a skill or attribute, sorted by
size; unlearned class skills are greyed out at 0%. Weapon arts list only
the damage types the held weapon deals and the held weapon's skill.
Tooltip line wrap ignores colour codes; art tooltips wrap wider.
Blitzschlag's tooltip rewrite becomes a tooltip filter.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/game/ui/texts.h

@@ -23,4 +23,13 @@ void ReplaceInTexts(const std::wstring& from, const std::wstring& to);
 // The game's text `id` without our changes (empty if there is none).
 std::wstring GameText(uint32_t id);
 
+// The game's text under key `key` (TextManager::GetTextByKey 0x672fd0), e.g.
+// "UI_ATTRIB_STRENGTH"; empty if there is none.
+std::wstring GameTextByKey(const char* key);
+
+// A game wide string ({begin, end, capacity end}, e.g. a tooltip's text) as
+// text, and replaced by `value` (grown with the game's allocator).
+std::wstring WideStringText(const void* string);
+void SetWideString(void* string, const std::wstring& value);
+
 } // namespace game